Tom Selleck was originally cast as Indiana Jones, but was not able to take the role because he was committed to "Magnum, P.I." (1980). "Magnum" did an episode that parodied "Raiders", complete with hat, whip, booby traps, etc.
Nick Nolte, Steve Martin, Chevy Chase and Jack Nicholson all turned down the role of Indiana Jones.
Steve Martin had a choice of doing this film or Pennies from Heaven (1981). He chose Pennies from Heaven (1981)
Bill Murray was offered the role of Indiana Jones, but turned it down due to his commitment to the TV series "Saturday Night Live" (1975).
The scene where Indy threatens to blow up the Ark with a bazooka as it is being carried through a canyon was filmed in the same canyon in Tunisia used in Star Wars (1977) when R2-D2 was zapped and stolen by Jawas.
A sheet of glass separates Harrison Ford and the arched (and highly dangerous) cobra when he falls into the Well of Souls. The snake actually did spray venom onto the glass.
The giant boulder that chases after Indiana Jones at the start of the film was made of fiberglass. On the Bonus Features DVD, sound designer Ben Burtt said that in order to get the proper sound effects for the giant boulder, he and the sound crew tried pushing boulders down a hill, but the sounds they were getting weren't up to par with what they were looking for, and later that day, as they were leaving in a Honda Civic that they coasted a car down a gravel embankment, and Burtt noticed that the sound was just what they were looking for, so he grabbed a microphone and held it near one of the Civic's rear tires to record the effect.
The spirit effects at the climax were achieved by shooting mannequins underwater in slow motion through a fuzzy lens to achieve an ethereal quality.
The original name of the lead character in the script was Indiana Smith. His name was changed to Jones on the first day of production.
The hieroglyphics in the Well of Souls include engravings of R2-D2 and C-3PO (from Star Wars (1977), etc). They can be seen on a post to the right of Indy and Sallah as they remove the Ark.
According to the director, when the movie was originally submitted for an MPAA rating, it was given a rating of "R" because of the sight of an exploding head. In order to lower the rating, flames were superimposed over this image. The result was the appearance of a head exploding behind a dense curtain of flames. The rating was lowered to "PG" (at the time, the PG-13 rating did not exist).
At the end of the film, when Indy and Marion are tied to the pole as the Nazi's and Belloq open the Ark, the dome-topped head of R2-D2 is resting on the top of the pole that they are tied to.
In the Raiders oral history published in Empire magazine, Frank Marshall said that they got the monkey to do the Nazi salute by putting a grape on a fishing pole and getting the monkey to reach for the grape, which was dangling just out of camera range. This took about 50 takes before it actually looked like a Nazi salute.
During the scene where Indiana threatens Nazis with bazooka, you can clearly see a fly creeping into the mouth of Paul Freeman, and he swallows it. Empire Magazine chose this scene as one of the most common scenes people press "Pause" button on their VCR for.
Steven Spielberg originally wanted Danny DeVito to play Sallah and DeVito was set for the role, but he had to drop out due to conflicts with "Taxi" (1978).
Steven Spielberg wanted Danny DeVito to play Sallah in the film, but DeVito couldn't do it. Later, DeVito stars as a second banana to Michael Douglas in the Raiders tribute/derivative, Romancing the Stone (1984).
Kauai, Hawaii, substituted for South America in the opening sequence of Raiders of the Lost Ark -– but production designer Norman Reynolds and associate producer Robert Watts also scouted locations in Puerto Rico, Guatemala and Mexico.
To shoot the scene on Sallah's roof, crew members had to remove 300 television antennas from homes in Kairouan, Tunisia. TV hadn't been invented in 1936.
The canyon in which Indiana Jones confronts Belloq and Nazis carrying the Ark was the same location used to represent Tatooine in Star Wars: Episode IV A New Hope.
In 1989, one of Indiana Jones's kangaroo-hide bullwhip was sold at Christie's auction house in London for $43,000.
The biplane in the opening of the film has the identification letters OB-CPO, a shout-out to Star Wars' Obi-Wan Kenobi and C-3PO.