The present study was mainly concentrated on the isolation and identification of bacterial antagonists from selected aerobic composts against L. theobromae, the bluish-black sapstain fungus. A previous study on the bacterial diversity of agricultural waste compost revealed a range of 105 to 109 bacteria per gram of compost in various stages of composting [29]. In the present study, the bacterial number (107/g) was found to be similar in all composts, and only seventeen visually diverse bacteria could be differentiated. This might be because of the ingredients used in the compost preparation. KFRI weed compost was prepared by aerobic composting of common weeds. KAU vermicompost and market available composts were obtained from dried leaves/cowdung and vegetable/fruit wastes, respectively. This supported findings on the effect of different compost material on bacterial growth [30].