The 30-share barometer, which gained 56.98 points in the previous session on Friday, moved down by 59.46 points, or 0.31 per cent, to 18,859.06, led by the weakness metals, capital goods, power and banking sector stocks.
Similarly, the wide-based National Stock Exchange index Nifty, moved down 22.50 points, or 0.39 per cent, to 5,697.20.
Brokers said besides profit-booking by speculators, a mixed trend at the Asian markets after US lawmakers failed to prevent the imposition of USD 85 billion in spending cuts that kicked in at the end of last week, influenced the sentiment.