The 30-share barometer declined by 84.12 points, or 0.42 per cent, to 19,651.65 with stocks of interest-sensitive such as banking, auto and realty sectors leading the fall. The Sensex had gained 449.23 points in the previous three sessions on expectations of rate cut.
The wide-based National Stock Exchange index Nifty down by 17.70 points, or 0.30 per cent, to 5,981.65.
Brokers said trimming of positions by participants before the Reserve Bank of India's credit policy, to be announced later today, mainly attributed fall in stock prices.
In the Asian region, Hong Kong's Hang Seng index gained 0.70 per cent, Japan's market is closed today. The US Dow Jones Industrial Average ended 0.89 per cent higher yesterday.