Efficiency of compost (corn stover amended with sheep manure) supplemented with sulphur, phosphate rock, gypsum and some bioagents (Bacillus subtilis, Trichoderma harzianum and arbuscular mycorrhizal fungi) was evaluated for suppressing powdery mildew of pepper under field conditions. Experiments were carried out under natural infection in the Experimental Farm of Sids Horticultural Research Station, Agric. Res. Center, Beni-Sweif governorate. Two different methods of application were used; soil amendment and or foliar spraying to reduce pepper powdery mildew and improving its productivity, as well as enhance soil fertility. All tested compost treatments reduced the number of infected leaves and powdery mildew severity as well as increased the yield compared to control treatment. On the other hand, spraying and amendment pepper plants during the growing season with compost combined with Trichoderma harzianum resulted in a significant decrease in disease severity of the disease with significant increment in pepper yield compared with the control treatment. In addition, combination the compost with Bacillus subtilis gave the best results in controlling powdery mildew of pepper.