Profit-booking at prevailing levels weighed.
The 30-share Sensex fell 80.09 points, or 0.27 per cent, to 28,812.88. The gauge had gained 737.41 points in the previous six sessions.
FMCG, auto, bank, power and metal stocks were trading in the negative zone, down by up to 0.67 per cent.
The NSE Nifty offered a similar picture, which was down 10.25 points, or 0.11 per cent, at 8,929.25.
A weak trend in other Asian markets cast its shadow as investors stepped back from a recent rally ahead of a speech to the Congress by Donald Trump this week.
Hong Kong's Hang Seng was down 0.53 per cent while Japan's Nikkei shed 1.16 per cent in early session today. Shanghai Composite fell 0.18 per cent.
The US Dow Jones Industrial Average, however, ended 0.05 per cent higher on Friday.