Colletotrichum capsici dan Erysiphe cichoracearum are two species pathogenic molds species on cultivation plants especially vegetables plant. The fungus can be controlled by the antagonist molds Trichoderma spp.. This research used Trichoderma viride, T. atroviride, and T. harzianum as antagonist molds. This research was done for: 1) analize the difference antagonism effect of antagonist molds Trichoderma spp. towards pathogenic molds C. capsici dan E. cichoracearum, 2) determine the Trichoderma species that have highest antagonism effect towards C. capsici danE. cichoracearum, 3) examine the antagonism mechanism of Trichoderma spp. towards kapang C. capsicidanE. cichoracearum based on the microscopic observation. The research methods use dual culture method by inoculate the antagonist mold : Trichoderma viride, T. atroviride, and T. harzianum and pathogenic mold, are: C. capsici dan E. Cichoracearumcolony pieceson PDA plate medium in pairs, then incubated on 25o-27oC for 4 x24 hours. Afterwards the antagonism effect of Trichoderma spp. towardsC. capsici andE. cichoracearumwere analyzed quantitative descriptive. The antagonism mechanism observed by Scanning Electron Microscope (SEM). The research results are: 1) there was difference antagonism effect of Trichoderma spp. towards C. capsici dan E. cichoracearum. 2) T. harzianum has the highest antagonism effect towards C. capsici as well as towards E. cichoracearum, 3) The antagonism mechanism of Trichoderma spp. towards C. capsici and E. cichoracearum by are mycoparasitism, the Trichoderma hyphae attach, penetrate, and coiling the C. capsici andE. cichoracearum hyphae