Extending losses for the fourth straight session, the 30-share barometer fell by 91.07 points, or 0.44 per cent, to 20,760.26 with IT, banking, power, metal and oil & gas sector stocks leading the fall.
The index has already lost 320 points in the past three sessions.
Similarly, the National Stock Exchange index Nifty shed 33.90 points, or 0.52 per cent, to 6,178.95.
Brokers said continued selling by funds as well as retail investors amid weak cues from other Asian markets dampened the trading sentiment here.
The US Dow Jones Industrial Average ended 0.17 per cent higher in Friday's trade.
