- Director Howard Hawks and star Humphrey Bogart got into an argument as to whether one of the characters was murdered or committed suicide. They sent a wire to author Raymond Chandler asking him to settle the issue, but he replied that he didn't know either. The question is left unresolved in the original novel by Chandler.
- The scene where Bogart and Lauren Bacall make suggestive talk about horses was added almost a year after filming was otherwise complete in an attempt to inject the film with the kind of risque innuendos that had made To Have and Have Not (1944), and Lauren Bacall, so popular a few years earlier.
- Mars' henchman are named Sidney and Pete, a tribute to Bogie's frequent costars Sydney Greenstreet and Peter Lorre.
- Eager to repeat the success of To Have and Have Not (1944), Jack Warner gave Howard Hawks $50,000 to purchase the rights for The Big Sleep. Hawks bought the rights for $5,000 and pocketed the rest.
- Raymond Chandler claimed that Martha Vickers gave such an intense performance as Carmen Sternwood that she completely overshadowed Lauren Bacall, and that much of Vickers' performance ended up on the cutting room floor as a result.
Please support TCMDB by adding to this information.Click here to contribute