Turkey's benchmark stock exchange fell 0.31 percent to open at 114,286.27 points on Monday.
Borsa Istanbul's BIST 100 index went down 358.35 points from Friday's close of 114,644.62 points.
The banking and holding sector indices lost value by 0.24 percent and 0.44 percent, respectively.
Among all sector indices, the textile leather sector index was the best performer, going up 0.39 percent while the transportation sector index has seen the biggest fall -- down by 1.48 percent.
The U.S. dollar decreased to 3.7550 Turkish liras at 9.30 a.m. local time (0630GMT), compared with Friday's closing rate of 3.7670.
However the euro-lira rate went up to 4.5880 from the previous day's close of 4.5650.
The price of Brent oil slightly increased to $69.92 per barrel on Monday morning, compared with $69.12 at the close on Friday.
Meanwhile TurkStat announced labor force statistics for October 2017 early Monday as annual unemployment fell to 10.3 percent, down 1.5 point year-on-year.
