Alternate versions

An extended version of the film contains ca. 8 minutes of extended/additional footage bringing it to 153 minutes total. The scenes include:

• The first dialogue between President Whitmore and Constance Spano was extended.
• A few sentences were added in the scene as Whitmore proposes to go to DefCon 3.
• The first added scene is a dialogue between David Levinson and a colleague at the TV station. He explains that an unknown signal is responsible for the bad TV broadcasting and that he may be able to block this signal.
• In the next extended scene Russell Casse meets his son after he was released from prison.
• Up next the dialogue between Jasmine and Tiffany in the strip club was extended.
• Then there is an extended dialogue between David and his father on the way to the White house. Right after this is an added scene in which David is searching for the number of Constance's handy.
• Another added scene features David and his father in the oval Office. The father is talking about the persons who visited this office. Actors, football players and now himself...
• Right after Jasmine found the truck, there is an added scene in which the illness of Russell's youngest son is described.
• The next added scene features Jasmine as she drives the truck and some survivors through the destroyed city.
• Later in Area 51 there is an added scene in which David Levinson and Dr. Brakkish Okun go into the alien spacecraft. Here the Doctor explains some of the alien technology.
• As Captain Steven Hiller arrives with the alien visitor, a scene was added in which Russell asks for a doctor for his ill son.
• The last extended scene shows Russell's daughter establishing a new friendship while the fight rages above Area 51.

In most versions shown in cinemas and also the ones available on video, scenes are missing that stress the global dimension of the alien attack. In these scenes, international tv-journalists report about the devastation in their respective countries, and the destroying of international cities is shown (e.g. Paris). The cast list still contains some of these reporters, e.g. it names Jessica Cardinahl as German reporter, and also Korean and Russian reporters. These scenes were interesting, as they illustrate that the aliens are not an American problem, but a global one.

The laserdisc special edition includes an alternate ending to the final aerial battle sequence. In it Russell Casse was rejected as a pilot for one of the jets to attack the alien ship approaching Area 51. However, he arrives at the end of battle flying his crop duster (which he has been towing behind his motor home) with a missile strapped to it. He then flies the crop duster into the energy beam weapon of the alien ship to bring it down.

In the original UK theatrical release during the closing sequence in the desert as Levinson (Goldblum) and Hiller (Smith) are walking towards the jeep, Hiller suggests to Levinson that he needs a new 'hero' walk and to swing his hips more. This dialogue, that explains Goldblum's odd walk, is missing from the video release

In the Australian/New Zealand video and theatrical release several shots were edited out so the film could receive a PG rating. These include the destruction of the AWAC as it enters the fire cloud and the shot of the helicopter pilots when the alien destroyer shoots them down. It was eventually released uncut still retaining it PG rating for the Blu-ray release.

Several of the media reports shown in the movie were actually shot on videotape (including special effects). A number of these scenes, plus others not in the movie, were edited together into a fake newscast that is available on the DVD release.

In the UK Television version of the film (possibly also VHS and DVD versions) all TV news reports are changed from the American broadcasts to Sky News broadcasts (a British news channel and, at the time of the movie, the only 24 hours news service in the UK)

In some cinemas in the Middle East, all scenes including Judd Hirsch were removed. In the film, Hirsch's character speaks Yiddish and wears the traditional Jewish yarmulke.