Mistry was unceremoniously sacked last month as chairman of TataSons, the holding company of India's most famous family conglomerate -- the $103 billion steel-to-salt Tata Group.
He continues to hold several chairmanships on boards of Tatacompanies however, including car behemoth Tata Motors, which owns Britain's Jaguar Land Rover, Tata Steel, Tata Power and its luxury hotel unit.
TCS said in a statement to the Bombay Stock Exchange that Tataveteran Ishaat Hussain had replaced Mistry as chairman "with immediate effect".
"Mistry has ceased to be the Chairman of the Board of Directors of the Company and Hussain is the new Chairman of the company," TCS said.
His removal as chairman of TCS, India's biggest IT outsourcing firm, comes as company patriarch Ratan Tata reasserts his authority over the sprawling conglomerate.
Mistry was sacked on October 24 with Tata unhappy at the directionMistry was taking the company in. The 78-year-old Tata, who led the group for more than two decades, has taken interim charge until a successor is found.
The pair have traded barbs since Mistry's ouster, plunging the group into bitter infighting with directors firmly placed in either camp.
Removing Mistry from various boards is not going to be easy however as he is heir to the multi-billion-dollar construction giant the Shapoorji Pallonji Group, which is the largest single shareholder in Tata Sons, owning 18.4 percent.
The Tata Group was founded under British colonial rule in 1868. It operates in more than 100 countries and owns high-profile companies such as Britain's Tetley Tea and Anglo-Dutch steel firm Corus.
