In independent Bangladesh, Tajuddin served as the Minister of Finance and Planning in Sheikh Mujib's Cabinet from 1972 to 1974. He was also a member of the committee drafting the Constitution of Bangladesh. He resigned from the cabinet in 1974 to live a quiet life. Following Sheikh Mujib's assassination in a coup d'état, Tajuddin was arrested and assassinated on 3 November 1975, along with three senior Awami League leaders in prison.