The 30-share barometer of the Bombay Stock Exchange fell by 57.14 points to 20,127.60 level in the opening trade today.
The Sensex had lost over 375 points in the past three trading sessions.
Similarly, the wide-based National Stock Exchange Nifty index also moved down by 19.60 points to 6,028.65 points.
Market analysts said sharp rise in food inflation to 18.32 per cent for the week ended December 25, 2010 and reports of weakening trend on other Asian bourses dampened the trading sentiment, triggering selling by funds and retail investors.
Stocks of capital goods, banking, auto and metal sectors in particular were under pressure and dragged the Sensex down.
Meanwhile, Hong Kong`s Hang Seng index was down by 0.14 per cent, while Japan`s Nikkei was trading 0.22 per cent lower in early trade today.
In the US, the Dow Jones Industrial Average ended 0.22 points lower in yesterday`s trade.