Zappa projected his unique vision on the nation's screens as the co-director of the cultish "200 Motels" (1971). A sometimes inspired but uneven product of the drug culture, the film featured extended concert sequences of Zappa and his group, The Mothers of Invention, between some wildly satirical sketches. "200 Motels" also boasted a raunchy animated sequence. His next cinematic effort, the surreal documentary "Baby Snakes" (1979), also displayed Zappa's odd brand of humor and a nifty stop-motion animation sequence by Bruce Bickford. Zappa's final film project was a documentary on clay animator Bickford, entitled "The Amazing Mr. Bickford" (1989), which he produced, directed, wrote, and supplied with songs.

During the mid-80s, Zappa became widely visible as a staunch defender of free speech in popular music, even testifying before a Senate sub-committee and the PMRC (Parents Music Resource Center) on "porn rock" and the labeling of albums that feature "explicit" lyrics. He likened their method of censorship to "treating dandruff by decapitation". Zappa's final years were spent in a public battle with prostate cancer to which he succumbed in 1993.