The 30-share barometer declined by 27.52 points, or 0.16 per cent, to 17,251.33, as stocks of auto, realty and refinery sectors fell on profit-booking after recent strong gains.
The Sensex rose by almost 176 points in the previous three sessions.
Similarly, the wide-based National Stock Exchange index Nifty shed 11.65 points, or 0.22 per cent, to 5,231.05.
Brokers said besides profit-booking by participants, mixed trend in Asian region also influenced the sentiment.
In the Asian region, Hong Kong's Hang Seng index was up marginally by 0.07 per cent, while Japan's Nikkei Index traded lower 0.29 per cent in early trade today.
