"I said that after (launching small-car) Nano, it will be a good time to step down...I still have a deadline for my retirement. I do have the responsibility to have a successor and both these things will take place," he told reporters here.
Tata, who had earlier said that the successor could be from outside India, had declared his intention to step down after the launch of world's cheapest car 'Nano'.
Nano made its commercial debut last year.
There have been speculation from time to time on who will succeed Tata at the USD 71-billion group that makes nearly everything from salt to steel to luxury cars.
Tata, who turned 72 last month, will stay in office till 2012.
The Tata group has 98 operating companies and 357,000 employees.