The film is dedicated to actress Barbara Ruick who appears in the movie as a barmaid and who died on location during the filming. The end title card memorializing this reads: "FOR BARBARA 1933-1973". She was married to composer John Williams, who had worked with Robert Altman the previous year on "The Long Goodbye". It is to be noted that a great many female characters in the film are called "Barbara", possibly in tribute to Ruick.
The film's 8-track stereo was instrumental in launching what would become one of Robert Altman's trademarks - overlapping dialogue.
To make George Segal feel the pain of losing, the director and writer set him up in a game against actual poker players, including the legendary 'Amarillo Slim' Preston (who appears in the Reno poker game) and made him use his personal money. They told him he was going to lose a couple thousand of his own dollars. But the cards ran his way, and Segal was the only winner in the game.
Writer Joseph Walsh worked on the script in its formative stages for 9 months with a young up-and-coming director called Steven Spielberg. In this early incarnation, the script was called "Slide".
Columbia had no idea how to market the film properly so pulled it from release after only a few short weeks. Nevertheless in that time, it managed to gross $5 million and ultimately found its way onto the ten best list of several critics at the end of the year.