Saudi Arabia's index posted its worst daily losses in the past month, amid a string of weak results.
The benchmark index fell 1.5% in its worst daily performance since June 24, accompanied by declines in all listed banks.
Saudi Arabia's Basic Industries Corp (SABIC), the world's fourth largest petrochemical producer, fell 1.6%, extending losses from the previous session after the company posted its lowest quarterly profit since late 2009.
Dallah Health Services Holding (6%) fell after the company reported a second-quarter profit decline, hurt by higher operating and financing costs, while Halwani Brothers fell 2.3% after Food changed to a loss in the second quarter attributed to higher cost of marketed products in the Kingdom And increased sales and distribution expenses in Egypt.