Sridevi and Kamal Hassan were a popular pair in South industry and worked in many films.Sadma remains their only Hindi film together.
AR Rahman was Ilaiyaraaja's assistant in the film.
Balu Mahendra initially wrote the climax as 'Kamal Haasan just looking at Sridevi sadly as she leaves' but Kamal felt it was a little too artsy/subdued for a film targeted at the mainstream audience. So he came up with the idea for the extensive climactic sequence which would leave the audience on an emotional high. That proved to be a master's stroke as that sequence is now legendary and part of the Tamil pop culture.
Anil Kapoor was shooting for a Kannada film and took Gulshan Grover along with him. Balu Mahendra was the camera man of the film. He asked Anil Kapoor to ask Gulshan Grover if he would be interested in a villain's role in Sadma. Gulshan immediately agreed. The role was originally suppose to be done by Stevie Ray and Sharat Saxena in the Hindi version.
The cult song "Poongatru Puthithanathu" was replaced with slightly different "Aye Zindagi Gale Laga Le" which itself went on to become a cult song in Hindi.