In the shot in which Saif Ali Khan is in the shadows, looking at a mirror, director Vishal Bhardwaj suggested that it would be very artistic and beautiful if Khan did it naked. The actor answered, "I am prepared to do that as long as you direct me naked." That was the end of the topic.
Initially, Aamir Khan was keen on playing the role of Langda Tyagi. He was set to play the role; but then director Vishal Bhardwaj dropped Aamir and signed Saif Ali Khan to play the role instead. This led to some tension between Aamir and Vishal for a while, but they later patched up with each other and are on good terms again.
Apparently Aamir Khan suggested the idea of the film to director Vishal Bhardwaj. At one point Aamir was going to co-produce the film with Vishal and play the role of Langda Tyagi as well, but later after a meeting with Saif Ali Khan, Bhardwaj decided to cast him for the role instead, causing Aamir to then step out of the picture.
The title of the film, "Omkara", was decided by a contest that was open to the public. Three names were shortlisted for the title and the general public voted in by SMS to choose their favorite. The selected names included "Omkara", "O Saathi Re" and "Issak" (the western UP pronunciation of the word "Ishq"). The public voted overwhelmingly in favor of "Omkara". However, all three of the possible titles are songs on the soundtrack ("Issak" being another name for the song "Namak").
Om Puri and Anupam Kher were both considered for the role of Bhaisaab before Naseerudin Shah was selected.