Tata, who will turn 75 on December 28, has also been conferred the honorary title of chairman emeritus by the Tata Sons board, the statement added.
Forty-three year old Mistry, son of reclusive billionaire Pallonji Shapoorji Mistry, has been a director of Tata Sons since 2006 and was appointed deputy chairman in November last year.
Pallonji, along with his sons Shapoor Mistry and Cyrus, controls an 18.5% stake in Tata Sons, making the Mistrys the conglomerates largest individual shareholders in Indias most diversified business conglomerate. Mistry has been a director of Tata Sons since 2006 and was appointed deputy chairman in November last year.
Earlier this month, Tata Motors had appointed Mistry as its chairman with effect from December 28 after Tatas retirement.