Animated hit Toy Story and action movie The French Connection are among films which have been picked for preservation by the US Library of Congress.
Toy Story introduced the world to Buzz Lightyear
Twenty-five films are picked for its National Film Registry each year, to preserve America's cultural heritage.
Also being saved for posterity are The Rocky Horror Picture Show, Buster Keaton comedy The Cameraman and teen comedy Fast Times At Ridgemount High.
Footage of the 1906 San Francisco earthquake is also being preserved.
The 1994 documentary Hoop Dreams, about inner-city Chicago youngsters vying for college basketball scholarships, is another choice.
This year's selections bring to 425 the number of films being preserved as part of the scheme, which began in 1989.
Controversial 1933 film Baby Face, starring Barbara Stanwyck as a siren seducing her way up the social ladder, was also chosen by Congress librarian James H Billington.
"The films we choose are not necessarily the 'best' American films ever made or the most famous, but they are films that continue to have cultural, historical or aesthetic significance," he said.
The selections came from 1,000 titles chosen by the public. Toy Story, released in 1995, is the most recent inclusion. It was the first full-length computer animated feature.
Mr Billington added that half the movies produced in the US before 1950 and up to 90% of those made before 1920 have disappeared, with more being lost each year, partly because of "vinegar syndrome", a chemical reaction which attacks the acetates in old film stock.
"Sadly, our enthusiasm for watching films has proved far greater than our commitment to preserving them," he said.