Single isolates of each of four species of Trichoderma and two species of Gliocladium and two isolates of each of Bacillus subtilis and Pseudomonas fluorescens were tested for the control cucumber stem rot disease caused by Sclerotinia sclerotiorum. All tested isolates significantly inhibited the radial growth of the fungus. The maximum inhibition was induced by T. hamatum (80.34%), G. virens (79.54%) and T.viride (79.31%) respectively, while G. deliquescens was the least effective (73.83%). The two isolates of. P. fluorescens (1,2) reduced the radial growth of the pathogen more than B. subtilis. Culture filtrate of each species of Tichoderma, Gliocladium and bacteria significantly reduced the mycelial growth and sclerotia formation. Soil treatment with 7.hamatum, G. virens or B.subtilis gave the maximum protection against the fungal infection followed by T.viride and P. fluorescens. Moreover, this treatment improved plant height and increased number of flowers as well as fruit yield. The biocontrol agents tested were nearly as effective as the fungicide Topsin M70.The seedling treatment with the bioagents was less effective than soil treatment in two seasons.