Nargis died in 1981 after a prolonged battle with pancreatic cancer. Tuesday marks her 81st birth anniversary.
"It's been 29 years now that my beloved mother left us. It's her b'day today. As I remember her each time, everything comes to me in flashes, " Sanjay posted on the microblogging site Twitter.
"Wishing my mom a lovely birthday. May god bless her soul. I know whereever she is, she must be happy. Love you ma."
Born as Fatima Rashid, Nargis made her screen debut as a child artist with "Talash-E-Haq" in 1935 and "Tamanna" (1942) was her first film as a full-fledged actress.
In her two-decade long career, Nargis appeared in several successful films like "Barsaat", "Andaz", "Awaara", "Deedar", "Shree 420" and "Chori Chori".
She is still remembered for her role in Mehboob Khan's Oscar-nominated rural drama "Mother India" that came in 1957. The following year she tied the knot with her co-star Sunil Dutt who played her son in the movie.