The 30-share index lost 221.29 points, or 1.19 per cent, to trade at 18,336.84 with banking, realty, metal PSUs and oil and gas sector stocks leading the fall. Sensex had gained over 652 points in the previous three sessions.
Similarly, the wide-based National Stock Exchange index Nifty declined by 80.95 points, or 1.48 per cent, to 5,395.55.
Brokers said sentiments turned weak on emergence of selling after the rupee again breached 65-level by falling 104 paise to Rs 65.34 against the dollar and a weakening trend on the other Asian bourses, tracking losses in US markets.
The US Dow Jones Industrial Average ended 0.43 per cent lower in yesterday's trade.