No less than nine writers worked on the script. Besides the credited writers Ted Elliott, Terry Rossio and David S. Goyer, work was also done by James Bonny, Michael Engelberg, Richard Finney, Neal Purvis, Robert Wade and the film's director, Stuart Orme. The final version mainly uses ideas from the Goyer and Orme rewrites.
The hive or the Central Intellegence home where everyone gathers to collect intelligence from their human hosts was actually a set built on the Disney lot. While the actual entrance of the nest was at the Los Angeles County Center, with styrofoam walls built there to make it look like it was taken over.
Some shots were filmed in downtown Des Moines, Iowa.
Many scenes involving meetings with Andrew, et al. were shot in Fresno, California. Keith David was not thrilled to be working there, stating "It's a good place to pass through, but working... no."
Several stars have previously been in films about alien parasites: Donald Sutherland in L'Invasion des profanateurs (1978), Yaphet Kotto in Alien, le 8ème passager (1979), and Keith David in The Thing (1982).