Satyen Kappu dubbed for the main villain' s voice to keep the suspense.
A cover version of the song "Brazil Lalala" (Aquarela Do Brasil) plays during a cabaret dance in the film. It was later recreated for Mr Natwarlal in the song "Oonchi Oonchi Baaton Se" .The song would gain major popularity 35 years later when Shakira did her own version.
Amitabh Bachchan's picture was no where on the original LP record album released. Only Jeetendra and Hema Malini were on the front cover.
Salim and Javed took Prakash Mehra to Rajkamal Studios where Amitabh was shooting for Gehri Chaal. They wanted to introduce Mehra to Amitabh and show him who they had selected for Zanjeer. Mehra was happy with what he saw and locked in Amitabh for Zanjeer.