Heavyweights SABIC and Al Rajhi Banks retreat 1.3 and 0.3 percent respectively
Saudi Arabia's index fell, as investors booked profits in petrochemicals after Thursday's rally, which was spurred by rising oil prices. Brent crude for June rose 14 cents on Thursday to settle at $123.99 a barrel, having earlier pushed up nearly $1 to $124.81, the highest since April 11.
The benchmark slipped 0.1 percent to 6,582 points, falling in two of past five sessions.
The Saudi benchmark has seen a long hiatus with equities tracking developments closer to home.
"We'll need to start seeing investors recoupling the Saudi petrochemical equity pricing to movements in the global market's economy and outlook," said Amro Halwani, a senior trader at Shuaa Capital in Riyadh.
Heavyweight Saudi Basic Industries Corp (SABIC) and Al-Rajhi Bank retreated 1.3 and 0.3 percent respectively.
Bucking the trend, Saudi Arabia's PetroRabigh gained 5.6 percent after Credit Suisse upgraded it to "outperform" from "neutral," citing a turnaround in refining margins of the joint venture between Japan's Sumitomo Chemical and Saudi Aramco.
PetroRabigh is also the most actively traded stock by volume.