The 30-share barometer fell by 71.11 points, or 0.35 percent, to 20,051.21 The index had gained 183.28 points in the previous two sessions.
Stocks of FMCG, capital goods, metal, auto, IT and realty sectors declined due to profit-booking.
Similarly, the wide-based National Stock Exchange index Nifty fell by 25.40 points, or 0.42 percent, to 6,081.85
Brokers said selling by funds amid mixed trend on other Asian bourses mainly influenced the trading sentiment.
They said Asian shares eased Monday with sentiment hit by selling in commodities triggered by a strong dollar, which rose to a fresh four-and-a-half-year peak against the yen on the back of growing confidence in the US economy.
In the Asian region, Japan's Nikkei Index was up 1.63 percent, while Hong Kong's Hang Seng index shed 0.82 percent in early trade.