The antagonism of 78 strains of Trichoderma against R. solani was tested by the dual culture method. None of the Trichoderma isolates caused an inhibition zone in a colony of R. solani, but most of them overgrew the mycelium of the pathogen and sporulated abundantly on its surface. Of the examined Trichoderma isolates, 83.3% were antagonistic to R. solani in vitro (Figure 3). Sixty two percent of the antagonists belonged to T. harzianum and 37 percent to T. virens. All T. harzianum isolates had a rating of 1 or 2, i.e. they were antagonistic