The objective of this study was to select the potential Trichoderma spp. and Bacillus spp. to inhibit Coletotrichum capsici causal agent of chili anthracnose. Soil dilution plate method could be used to isolate Trichoderma spp. and Bacillus spp. from ten chili fields, Mahasarakham province. Three isolates of Trichoderma spp. and forty isolates of Bacillus spp. were isolated and used to fungal inhibition test by using bioassay technique. The highest competition activity could be obtained from Trichoderma – TR2 and TR5 while antibiosis and competition activity were found from Trichoderma-TR3. Only 4 isolates of Bacillus spp., BSR1-1 BSR5-5 BSR3-6 and BSR4-6 gave antibiosis activity to inhibit colony growth of all tested Colletotrichum capsici, respectively.