• When Logan is drinking his Doctor Pepper while talking to Iceman, his grip on the bottleneck alternates between shots.
• Wolverine takes the soda from the cabinet and pops the top off. Before taking a drink, he hands it to Bobby (Iceman) to cool it off for him. In the next shot of Iceman, Wolverine's arm, and the soda bottle, the amount of soda has noticeably decreased. In the third shot, we see Wolverine and the now icy bottle with the soda level returned to the same level as the first shot.
• When the X-men jet is trying to dodge the rockets, there are a few close-ups of Bobby showing that the seat in front of him is empty. In other shots before and after the close-ups of Bobby, it shows that Rogue is sitting in that "empty" seat.
• While the X-Men are running away from the lab, Jean's limp disappears during one shot.
• During the "crash landing" of the plane, Rogue's seatbelt changes position between shots.
• During the attack on the school, one of the soldiers opens fire in the kitchen and the Dr Pepper bottle on the counter changes places between shots.
• Nightcrawler is visible in the shadows behind the children before he and Storm arrive at the cell.
• Nightcrawler's face is white in his first appearance because the character is wearing makeup to disguise his blue skin. A later shot of him through a gap in a door shows that most, but not all, of the makeup has been wiped away, and some has run from the character sweating.
• When Professor X visits the plastic prison, Magneto's face is very badly bruised. By the time he meets up with the rest of the X-Men his face is completely healed, even though it's less than a day later.
• Towards the end of the scene where the mansion is invaded by Stryker, Bobby, Rogue, Pyro and Wolverine are running to the secret passage. As they run down a corridor, a camera is clearly visible moving into the roof of the set.
• As water begins to leak into the underground tunnel, Stryker removes his glasses and a close-up shows several drops falling onto one lens. When he replaces his glasses, both lenses are dry.
• Since Senator Kelly died in the middle of the first movie, his subsequent appearances have been impersonations by Mystique. But any U.S. Senator's personal and political obligations fill up nearly every waking hour. Given that there is only one Mystique, and that she impersonates several other characters in addition to appearing as herself, "Senator Kelly" frequently disappears for hours or days at a time. In the real world or even the comic book world, her intermittent use of Kelly's likeness would be quickly uncovered as bogus by his family or staff.
• When Magneto is changing the metal plates in the underground Cerebro with his magnetic powers, he ascends with a cape on his back. Yet, when he descends, he's not wearing the cape any longer.
• In the scene in the lab where night crawler is going to save the kids in the cage below, you see him in the shadows of the cell in an inside close-up, but in the next shot, he is on top of the bars. Then, when he is about to teleport into the cell, you can see him again in the close-up of the cell shadows, then emerging from the same shadows.
• When Stryker visits Magneto to interrogate him, he enters Magneto's cell while still wearing his glasses, which have metal legs. The scanning process should have caught that on his way in; if it hadn't, Magneto should be able to manipulate them and use them to escape. It was shown in the first movie that Magneto can manipulate even non-ferrous metals, so he should have been able to affect Stryker's glasses.
• In the beginning Wolverine's hair and beard change between shots.
• On the X Plane before the missiles hit it, Rogue scrambled to get her seat belt buckled. However, after the first plane flip, she's sitting with a smile on her face, hands in her lap, no worries. Then she's shown again gasping and holding the belt buckles with both her hands.
• In the scene where the X-Men are in the President's office at the end of the film, they hand him a blue folder. When they have left and time begins moving again, there is a green folder and random papers on his desk. The next time we see his desk there is only a blue folder neatly placed in front of him.
• In the original X-Men, Wolverine is able to spot Mystique twice by catching her scent. Once when she disguised herself as a small Statue of Liberty, and another time as Storm. Yet, he does not catch Mystique by scent when she masquerades as Jean Grey and tries to seduce him. Clearly his own feelings for Jean and this sudden arousal threw him off and kept him from sensing the impersonation.
• Rogue and Nightcrawler would have fallen against the dash or jolted forward when Magneto stops the ship from crashing.
• When Wolverine extinguishes his cigar on his hand, the end of the cigar that he pulls away from his hand is the end that was not lit.
• In the scene where Wolverine takes the cigar and burns his hand with it, you can see a cut on his finger. But because he can heal all of his wounds he shouldn't have that cut.
• When all the X-Men and Xavier are talking with the president, supposedly everyone who is not an X-Man is frozen or time has stood still but in one shot you can clearly see someone blink a couple of times.
• In the bar, the TV is showing a debate on the mutant situation. One of the panelists is "Dr. Hank McCoy," which is the real name of the blue-furred behemoth X-Man, Beast. The other, not seen but called "Dr. Shaw," is presumably Dr. Sebastian Shaw, the leader of the Hellfire Club in the comics.
• On Yuriko's computer, the following files are listed: Guthrie (2) (Paige (Husk), and Samuel (Cannonball)); Harada, Keniucho (Silver Samurai); Kane, Garrison (Weapon X); LeBeau, Remy (Gambit); Lensherr, Eric (sic) (Magneto); Maddicks, Artie; Madrox, Jamie (Multiple Man); Xi'an Coy Mahn(Karma);Maximoff (2) (Wanda (Scarlet Witch), and Pietro (Quicksilver)); McTaggart, Kevin (Proteus); Moonstar, Danielle (Moonstar); Munroe, Ororo (Storm); McCoy, Hank (Beast); Callasantos, Maria (Feral); Cassidy (2) (Sean (Banshee), and Tom (Black Tom); Cheney, Lila; Creed, Victor (Sabretooth); DaCosta, Roberto (Sunspot); Dane, Lorna (Polaris); Drake, Bobby (Iceman); Dukes, Fred (Blob); Espinosa, Angelo (Skin), and; Gibney, kyle (Wild Child). On another screen there were a series of folders on the computer's desktop. These folders listed some well-known individuals or places from the X-Men universe, including: Omega Red (Russian mutant super soldier), Muir Island (Scottish mutant research facility), Project Wideawake (Codename for Sentinel project), Franklin Richards (son of Fantastic Four's Reed Richards and Sue Storm; born a mutant), and Cerebro (mutant tracking device created by Professor Xavier and Magneto). Closer inspection reveals that Stryker is keeping files on Pyro, Sabra, Dr Ceclia Reyes, Synch, Penance, Nightcrawler, his own Mystique and Lady Deathstrike, Copycat, Deadpool, Cyclops, Dazzler, the von Struckers, Jamie Braddock, David North, Sunfire, Boom Boom, Mimic, Dr Nathaniel Essex, Toad, Wolfsbane, Strong Guy, Kitty Pryde, Sauron, Forge... Curiously, there seem to be no files for Jean Grey or Wolverine, among others. There are also files on Alpha, Beta and Gamma Flights, Weapon X, Project Wide Awake (sic), Dept H, the Brotherhood, Graymalkin, Zero Tolerance, Massachussets Academy, Blackbird, the Danger Room, Legacy, Morlocks, Xavier's School, Omega Red, Cerebro, the Salem Centre, Franklin Richards, Kevin McTaggart, and of course Trash.
• Alan Cumming had to endure 10 hours of make-up to become Nightcrawler for the scene in the church (where his skin/make-up is shown from the waist up).
• Professor Xavier's wheelchair from the first movie was bought by a lawyer (who also works for the same law firm as Patrick Stewart's attorney). When production began, the studio realized they had no chair anymore, so the lawyer rented it back to the studio - as Stewart said in an interview - "for a significant sum".
• The "Lady Deathstrike" claws were glued to the bottom of Kelly Hu's own fingernails. She had to grow them out a bit so that the claws would fit securely.
• Hugh Jackman was given a nutritionist to get in shape for his role as Wolverine and gained 20 pounds.
• Rebecca Romijn's make-up took five hours to apply.
• The fight between Wolverine and Yuriko took three weeks to film.
• Jean Grey's closing monologue is the same as Professor X's opening monologue in X-Men (2000).
• When Wolverine is in the kitchen in Bobby Drake's parents' house, and he is surprised by the cat, he lets it lick his claws - seemingly a very cute moment. But if you listen closely when he hears someone come in and retracts his claws, you hear the sound effect of Wolverine's claws extending (if you listen closely, you can tell the difference, as the retracting sound is the same as the extending sound, but played in reverse), and then the cat crying out. This was an unintentional moment of comedy which was going to but cut but the last minute decision was made to leave it in.
• The Arctic snow scenes were filmed in Alberta, Canada, an area known for its heavy snows. Naturally when the production arrived, there was none, so the snow had to be recreated.
• Most of the actors from the scene in the museum where Professor X freezes everyone were actually mimes, who are used to not moving. Likewise, mimes were used for the final scene in the Oval Office.
• Kelly Hu has only one line of dialogue in the entire film.
• Unlike the first film where Rebecca Romijn wore contact lenses, this time Mystique's eyes are rendered digitally.
• The set for Stryker's underground lair was built in an old Sears warehouse and was the largest set in North America. It involved over 60 miles of cable and was so large that cast and crew members used bicycles to get them to and from the bathroom as quickly as possible. Even then, the production only used about half the space in the warehouse.
• Frozen tea was put on the end of Wolverine's claws for the cat at Iceman's home to lick off.
• The script went through 27 drafts.
• They had to shoot Professor X's pristine Cerebro set first before distressing it to show Stryker's cut-price version.
• The red scar on the back of Cyclops' neck to signify his being controlled by Stryker was added digitally afterwards.
• Another huge set was the turbine hall of an old dam which housed a museum. Unfortunately the museum was painted in bright, lurid colors, so the production design team had to dress it up to make it look old and dank (something which horrified the museum administration until they realized that it was just temporary).
• The adamantium that pours out of Lady Deathstrike's face is CGI and that's a highly detailed mannequin of her that falls down into the bottom of the tank.
• Bryan Singer insisted that the writers do proper research on what would happen if a dam was breached. Remarkably, they found plenty of information about that on the Internet.
• Health and safety restrictions meant that helicopter blades were not allowed to be moving when the actors - in this case, Rebecca Romijn and Ian McKellen - were sitting inside the helicopter. The moving blades had to be added in digitally afterwards.
• Originally the idea was that Jean Grey was temporarily rendered blind after her violent reunion with Cyclops. This was initially filmed as such, but ditched during production, but in the scene where Wolverine shuts a dam door, saving the X-Men from a wall of water, Jean Grey is the only character not looking at him.
• The replica of the President's desk in the Oval Office was so detailed that it took two months to build.
• In an effort to keep the ending a secret up until the movie came out, the novelization and the movie comic both have different endings.
• Several sets for the film were not used. Some of these sets included the Danger Room and several areas in Stryker's underground bunker. One room in Stryker's underground base was going to be the setting of a Nightcrawler vs. Toad fight.
• The animated movie being shown on the video monitors in the museum in the opening is Why Man Creates (1968). The segment being shown is a quick history of human culture.
• Director Bryan Singer credits the X-Men graphic novel "God Loves, Man Kills" as an influence for the script.
• An early draft of the script had Magneto saving Professor X from Dark Cerebro and escaping with the other X-Men. According to director Bryan Singer his was changed late in production not only to remain true to Magneto's ruthless character, but also to give the other characters--namely Nightcrawler and Storm--something more to do in the film's climax.
• The car that Wolverine drives (which, according to Iceman, belongs to Cyclops) is a Mazda RX-8. The X's in the rims where made especially for the movie.
• Shortly before the opening assassination attempt on the US president, a number of portraits of past assassinated presidents are featured in the background: Abraham Lincoln, John F Kennedy and William McKinley.
• When Mystique is going through the files in Stryker's computer, she goes through the pictures of the guards in Magneto's prison. The second to the last picture shows the director Bryan Singer, complete with guard uniform. His name is shown as "Singer, B."
• On "The Tonight Show with Jay Leno" (1992), Hugh Jackman related a story about something that happened during the filming of the Weapon X flashback scene: while he was filming the corridor run (in which he is nude and backlit), he turned the corner and saw the female cast members, including James Marsden's mother, waiting for him, hooting and waving dollar bills.
• The mansion used for the school also appears as Lex Luthor's home in "Smallville" (2001).
• There was an extended scene that doesn't appear in the final film, nor as a deleted scene on the DVD that features Cyclops's fight with Yuriko (Lady Deathstrike), where he picks up and fights with the two prison guards' plastic nightsticks.
• Wolverine's dog tag number is 458-25-243.
• The set from the bathroom scene where Mystique incapacitates the prison guard and injects him with a foreign substance is actually an unused set from X-Men (2000). The scene in question (written and storyboarded, but not shot) involved Cyclops manifesting his powers as a teenager, destroying a high school bathroom.
• When Jean and Storm are in the church looking for Nightcrawler, Jean is wearing a jacket with a phoenix on the back. This is a nod to the fans of the comic book where Jean becomes Phoenix.
• Alan Cumming was Bryan Singer's first choice for the role of Nightcrawler. However, during initial casting, he was unavailable. The project labored in development long enough that by the time the film was ready to shoot, Cumming was able to come onboard. Ethan Embry was rumoured to have won the role before Cumming was available.
• David Kaye who voices Professer Xavier in the television show, "X-Men: Evolution" (2000), appears as a TV announcer.
• When Pyro destroys the police cars, mixed in with the explosion sound effect is the sound of a pig squealing.
• Most of the exterior shots of the Xavier mansion were recycled from the first movie because there was no budget for them.
• The final scene in Xavier's mansion with Cyclops, Wolverine and Professor X was shot at Shepperton Studios in London, simply because Hugh Jackman was shooting Van Helsing (2004) at the time and the producers released him for only one day to do the final shooting of X-Men. The reason Wolverine's hair looks higher than usual in this scene is because Jackman had long hair for Van Helsing and had to wear the Wolverine wig over a lot of hair.
• According to director Bryan Singer, this is the first film to feature a woman piloting an American military aircraft, but it isn't.
• Bruce Davison (Senator Kelly) and Brian Cox (William Stryker) were born only 27 days apart, but Cox's character indicates that Senator Kelly is at least 20 years his junior.
• When Wolverine visits the adamantium processing chamber of Stryker's Alkali Base, there is a wall covered with x-rays detailing the adamantium bonding process. On the far right is an x-ray of what appears to be a left wing. The DVD acknowledges this as a hint to a winged character named Angel. In the comic books, Angel's wings are replaced with metal ones and he becomes Archangel.
• In the scene at the bar, the foam in the beer is fake. Singer chose to do this to avoid continuity conflicts.
• Entered into The Guinness Book of World Records as "The Widest Film Release" having opened on May 2, 2003 on 3,741 screens on the same day.
• The character Rogue, whose real name has never been revealed since her introduction in the comics in 1981, was given a name for this film - Marie D'Ancanto. Comic writer Chris Claremont, Rogue's creator, has used this name since the movie's release in the "X-Treme X-Men" comic, but for a different character.
• This is the only X-Men film where Stan Lee, creator of the original comics, doesn't appear.
• Rebecca Romijn and Sam Elliot have both played major and supporting roles as different characters throughout the Marvel Universe. Sam Elliot played a major role as General Ross in Hulk, and a supporting role as the Caretaker in Ghostrider. Rebecca Romijn had a major role as Mystique in all 3 X-Men movies, and played a supporting role as Joan (Frank's neighbor) in The Punisher.
• Ian McKellen (Magneto) worked with screenwriters to make the scene in which Bobby Drake (Iceman) tells his parents he is a mutant to look more like a common gay "coming-out" scene.
• Director Bryan Singer stated that he was inspired by the "The Twilight Zone" (1959) episode "The Howling Man" when making the scene where Senator Kelly transforms into Mystique. In the episode, an old man progressively changes into the devil while walking by pillars.
• In the final classroom scene, Professor Xavier talks about a book called "The Once and Future King" by T.H. White. This is the same book Magneto was reading in prison before Stryker's interrogation.
• The White House oval office is an exact recreation, but the corridors in the opening chase between Nightcrawler and the Secret Service, were wider than the actual walls to allow more room for fighting.
• Beast and Gambit were considered as new characters but they ultimately went with Nightcrawler because he was the most outsider-like of the choices.
• Pyro's cigarette lighter has a shark design on it; this is a tribute to director Bryan Singer's love of the movie Jaws (1975).
• The Oval Office set used in this film was later used in several episodes of the sci-fi TV-series "Stargate SG-1" (1997)
• The ice wall separating Wolverine (Hugh Jackman) and Stryker (Brian Cox) in the mansion scene where they meet for the "first time" was real ice and weighed 3,500 lbs.
• Magneto's line "When will these people learn how to fly?" is a reference to the fact that some of the characters (Jean Grey and also Rogue, who gets the ability from permanently absorbing Ms. Marvel's powers in the comics) have the ability to fly in the comics but haven't yet in the films. The only characters with the power of flight in the comics that have shown this ability in the movies are Magneto and Storm.
• When Mystique reviews the information on the security guards at the facility housing Magneto, the following names are displayed, referencing crew members of the film: DeSanto, T. (Tom DeSanto, executive producer); Dougherty, M. (Michael Dougherty, screenwriter); Donner, L. (Lauren Shuler Donner, producer); Young, R.D. (possibly Rob Young, production sound mixer); Harris, D. (Dan Harris, screenwriter) C. L. G. - Classified; R. G. M. - Classified, and; Singer, B. (Bryan Singer, director). Bryan is the only one who gets his own photo - the others, including Ms. Donner, are given stock male guard photos.
• According to Bryan Singer's commentary, he removed a couple of seconds of footage after Wolverine stabs a soldier in the kitchen during the raid for ratings purposes. But the extended sequence can be seen as deleted footage in the Supplemental Features disc. The extended sequence was also featured in the theatrical version in other countries (ex: Brazil).
• The music played in the opening scene when Nightcrawler attacks the White House is "Dies Irae" from Mozart's Requeim.
• Initially, during the "Dark Cerebro" scene where it is attempting to kill all mutants, Bryan Singer had planned to show not only Cerebro's effects on the mutants in the Alkali Base, but mutants all over the world. During this scene, Hank McCoy, aka Beast (Steve Bacic), as seen earlier on the television during the bar scene, was to be shown in agony, transforming into his furry form, and fan-favorite Gambit was to be shown at a card game having his energy powers flare up. This scene was actually shot, using one of Hugh Jackman's stunt men, James Bamford as a stand-in for the role, shot from behind to remain ambiguous. For whatever reason, Singer decided to cut this sequence altogether and it remains unseen.
• The illusion-casting powers that Mutant 143 (played by 'Michael Reid McKay' ) possesses, is a homage to a classic X-Men villain from the comics named Jason Wyngarde/Mastermind.
• The Danger Room, the area where the X-Men train and hone their powers, was going to be included in this film. Bryan Singer had wanted it to appear in the first film, but due to budget cuts, the idea had to be scrapped. It was then worked into the story for this film, to take place when Wolverine is left to watch after the students in the mansion. He decides to do a workout in the Danger Room, which was going to segue into the scene of him lying down and having a vision of Stryker and his Weapon X procedure. The Danger Room was going to be a cylindrical-shaped room, with different sections of the floor raising and lowering at dangerous speeds, as well as holographic projectiles, etc. The earliest teaser trailer for the film gave a sneak peak at how the Danger Room was going to look, but shortly after this teaser was released, Fox cut Singer's budget down from $125 million to $110 million, forcing Singer to once again cut the Danger Room from the film. There is still a small reference to the Danger Room remaining in the film: when Stryker first enters the X-Mansion subbasement, directly opposite from the elevator is a door with a small label on it, which, according to Singer's DVD commentary track, identifies the door as the entrance to the Danger Room.
• Neil Patrick Harris auditioned for the role of Nightcrawler, but lost out to Alan Cumming who speaks fluent German.
• Kurt Wagner's x-rays are all given the same id: C13957. They are all dated May 22/84, and taken my Dr D.Mintz (69) at the offices of "Drs Green, Chetwynd, Gough, Switzer, Siu, Fulton, Bentley, Murray. Radiologists. Vancouver, BC"
• The radio in the X-jet that Storm tunes is a Garmin 530, an actual communication/navigation radio commonly found in light aircraft.
• The song Pyro turns on in Cyclops' car is Bye, Bye, Bye by the pop band Nsync.
• In the scene where Rogue is sucked out of the jet, the stunt was performed by Anna Paquin herself and not a stunt double.
• Body count: 26
• The sunglasses worn by Cyclops are Oakley Pennys, although they look very similar to the glasses he wore in the original X-men they are in fact a different model (with Oakley Juliets appearing in the first film), both were modified with blinders around the lens. Oakley were also responsible for manufacturing the visor which Cyclops wears and in some shots Oakleys logo (a horizontally stretched "O") can be seen on the parts of the visor that cover Cyclops' ears.
• When Jean is hearing people's thoughts in the Science Museum, one of them is "To the shelter!" This line was said by one of the Secret Service during Nightcrawler's attack on the Oval Office in the previous scene, thus adding/alluding to Jean's growing psychic abilities.
• Bryan Singer cast Brian Cox as Stryker based on his performance in Manhunter (1986).