The 30-share index rose 52.62 points, or 0.25 per cent, to trade higher at 21,223.30 points with all the sectoral indices led by metal and capital goods trading in positive zone with gains up to 0.53 per cent.
The Sensex had gained 27.67 points in the previous session.
The broad-based National Stock Exchange index Nifty rose 12.80 points, or 0.20 per cent, to 6,316.80.
Brokers said sentiments remained firm on sustained buying by funds and retail investors largely in tandem with record closing on the US markets after upbeat economic data in yesterday's trade.
The US Dow Jones Industrial Average closed at another record high by gaining 0.44 per cent in yesterday's trade.