Compost was used as soil treatment either single or mixed with Trichoderma harzianum, Pseudomonas flourescens and Glomus sp. to study their efficiency against guar (Cyamopsis tetragonoloba) root rot caused by Sclerotium rolfsii. In vitro, among different bacteria isolated from compost wash, two isolates showed strong inhibitory effect against mycelial growth of S. rolfsii and were identified as Bacillus subtilis and B amyloliquefaciens usingGenetic analyzer (Applied Biosystem, Hitachi 3500).In the present work, mixed compost and bioagents was used to decrease disease incidence of root rot in guar plants. In pot experiments, soil amended with compost alone or mixed with bioagents provided a good protection against root rot. Soil amended with compost mixed with T. harzianum or P. fluorescens were superior that produced 82.35% and 76.48% decrease, respectively. Microbial population in the plant rhizosphere increased significantly as a result of application of compost alone or mixed with bioagents. Negative correlation was found between disease incidence and microbial population in the rhizosphere. Also, Soil amended with compost alone or mixed with bioagents increased plant nutrient uptake and improved soil fertility (NPK). Marked decrease in sclerotia germination of the pathogen in the soil amended with compost alone or mixed with bioagents was recorded. Soil amended with compost mixed with T.harzianum or P. fluorescens completely inhibited sclerotia germination. The aforementioned treatment not only decreased disease incidence but also increased fresh and dry weights of the plant as well as number of nodules compared to untreated control. Pilot field experiments are required.