The 30-share barometer added 51.16 points, or 0.27 per cent, to 18,875.07 with stocks of healthcare, PSU, IT and power sectors leading the rise.
The index has gained nearly 245 points in the previous two trading sessions. The markets were closed yesterday on account of 'Gandhi Jayanti'.
The wide-based National Stock Exchange index Nifty moved up by 17.70 points, or 0.31 per cent, to 5,736.50.
Trading sentiment remained bullish on continued buying by funds and retail investors, anticipating announcement of more economic reforms by the government, market experts said.
A firming trend in Asia also triggered buying activity, they said.
In Asian region, Hong Kong's Hang Seng rose by 0.67 per cent, while the Japan's Nikkei by 0.10 per cent in early trade today.
The US Dow Jones Industrial Average, however, had ended 0.24 per cent lower in yesterday's trade.