- The technical consultant for the film was Frank R. Bowerman, who was president of the American Academy for Environmental Protection at the time.
- The scene where Thorn and Roth share a meal of fresh food was not originally in the script, but was ad-libbed by Charlton Heston and Edward G. Robinson at director Richard Fleischer's request.
- The videogame in Simonson's apartment, "Computer Space", was one of the first coin-operated videogames, manufactured by Nutting Associates in 1971 and designed by Nolan Bushnell, who later founded Atari and designed "Pong". The videogame was painted white for the movie but the original color was either yellow, red or blue.
- One set of scenes in the original release, where a second family is housed with Thorn and Roth, was deleted from later copies of the film.
- The original title of Harry Harrison's book, "Make Room! Make Room!" was changed by the producers, who feared that audiences would confuse it with the 'Danny Thomas' TV series "Make Room for Daddy" (1953).
- Edward G. Robinson was almost totally deaf when he made this movie, and only able to hear anyone if they spoke directly into his ear. Because of this, scenes with him talking to other people had to be shot several times before he got the rhythm of the dialogue and was able to respond to people as if he could really hear them. And because he was unable to hear director Richard Fleischer yell "cut" when a scene went wrong, Robinson would often continue acting out the scene, unaware that shooting had stopped seconds earlier.
- The word soylent is supposed to suggest soy + lentil.
- All of the dialogue for actor Mike Henry ("Sgt. Kulozik") was dubbed. The actor's slight Southern drawl did not fit in with the New York cop character he was playing.
- Among the buildings in the matte "skyline" in the background of the early scene where Gilbert crosses the drainage ditch, one can see the Marina City towers (Chicago) and the Transamerica Pyramid (San Francisco).
- Edward G. Robinson's final film performance.
- The last film shot at MGM studios.
>>> WARNING: Here Be Spoilers <<<
Trivia items below here contain information that may give away important plot points. You may not want to read any further if you've not already seen this title.
- SPOILER: One of the scenes of the "beautiful earth" shown to Sol as he is dying is an opening shot from Far from the Madding Crowd (1967) (a flock of sheep on a green hillside).
- SPOILER: When Thorn discovers that he is too late to stop Sol's suicide, he begins to cry. Charlton Heston was really crying
- he was the only person on set who knew Edward G. Robinson was dying of cancer. His death scene was the last day he worked in his life; he died just nine days after shooting wrapped.
- SPOILER: The music which played when Edward G. Robinson was "going home": - The overture was the principal theme from the first movement of Tchaikovsky's Symphony No. 6, the "Pathetique." - When the visual presentation starts, the music is the first movement of Beethoven's "Symphony #6 (The Pastoral)". - When the flock of sheep appear, the music is "Morning" from Grieg's "Peer Gynt Suite #1". - At the end of the presentation is "Asas Death", also from the "Peer Gynt Suite".
- SPOILER: The movie's line "Soylent Green is people!" was voted as the #77 movie quote by the American Film Institute (out of 100).
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