The 30-share barometer, which had lost 573.21 points in the past four sessions, fell by 183.74 points, or 0.88 per cent, to 20,482.41.
Stocks of banking, realty, capital goods, metal, auto, oil and gas sectors were the major losers that dragged down the Sensex.
Similarly, the National Stock Exchange index Nifty fell by 69.90 points, or 1.13 per cent, to 6,070.85.
Brokers said sustained selling by foreign funds as well as retail investors and a weakening rupee which again breached the 63 mark against the dollar, continued to dampen the trading sentiments. The rupee was trading 60 paise down at Rs 63.07 a dollar.
The US Dow Jones Industrial Average ended 1.08 per cent higher in the previous session on Friday on strong US jobs figures.