Abstract: In biocontrol essays on cyclamen leaf disks,Clonostachys rosea and Trichoderma koningii suppressed Botrytis cinerea by 94%—100％,and were more effective than most fungi and bacteria isolated from cyclamen.Biocontrol effectiveness on whole plants showed that C.rosea suppressed B.cinerea in leaves,petals,petiole,and pedicels by 96％,58％,53％,and 77％,respectively and T.koningii by 100％,42％,100％ and 90％,respectively.The effects of inoculum concentrations of B.cinerea interacting with C.rosea or T.koningii respectively on biocontrol were examined in factorial design experiments.C.rosea suppressed B.cinerea in lamina,petals,petiole,and pedicels by 73%—100％,52%—86％,100％ and 54%—68％,respectively,when inoculum concentration of the antagonist was 10 times more than that of the pathogen.When inoculum concentration of T.koningii was at or over 106 conidia／mL,it suppressed B.cinerea at concentrations of 103—106conidia／mL in lamina by 100％,in petioles by 62%—100％,in petal by 38%—96％ and in pedicels by 56%—100％.C.rosea was more effectively on 2,3,5 and 6 weekold leaves,but less effective on 4 weekold leaves and no effect on 1 weekold leaves.T.koningii suppressed B.cinerea on 1 to 6 weekold leaves very effectively ranging from 89% to 100％.We concluded that C.rosea and T.koningii were potentially effective biocontrol agents against B.cinerea in cyclamen in greenhouses,but the effectiveness of T.koningii was significantly better than that of C.rosea.