Mazdoor is a romantic social family drama. The movie follows the story of Dinanath Saxena (Dilip Kumar), a labourer turned businessman. After having a conflict with his ex-employer, Dinanath Saxena decides to start his own business and gets success. One of his employees Ashok (Raj Babbar) helps Dinanath with his business and later, marries Dinanath’s daughter Smita (Rati Agnihotri). However, sometime later, Smita and Ashok start facing problems in their married life. Will Dinanath be able to mend his daughter and son-in-law’s relationship?