The objective of this study is to isolation and agonistic test ability of Trichoderma spp. againts Sclerotium rolfsii Sacc. cause of wilting on pepper plants and has been conducted in Pathogenicity Laboratory Faculty of Agriculture Unpatti. The study use 5 treatment of isolate Trichoderma spp. (Tc3, Tc4, Tc5, Tc6 and Tc7) with 3 replications so that there are 15 experimental units. The results showed that the five isolates Trichoderma spp. has an antagonistic power to S. rolfsii with an average percentage of inhibition of S. rolfsii of 26,01%. Percentage of inhibition bolth of isolate ware not significantly different at 95% level test results between treatment. Average percentage inhibition of S. rolfsii by Trichoderma spp. each treatment was Tc6 = 27,31%, Tc3 = 26,63%, Tc5 = 26,05%, Tc7 = 25,69% and Tc4 = 24,37%. Keywords: antagonism, Trichoderma spp., Sclerotium rolfsii   Abstrak Penelitian ini bertujuan mengisolasi dan menguji kemampuan antagonis Trichoderma spp. terhadap Sclerotium rolfsii Sacc. penyebab layu pada tanaman cabai dan telah dilaksanakan di Laboratorium Patogenisitas Fakultas Pertanian Unpatti, dengan menggunakan 5 perlakuan isolat Trichoderma spp. (Tc3, Tc4, Tc5, Tc6 dan Tc7) dengan 3 ulangan sehingga terdapat 15 satuan percobaan. Hasil penelitian menunjukkan bahwa kelima isolat Trichoderma sp. mempunyai daya antagonis terhadap S. rolfsii dengan rata-rata persentase penghambatan S. rolfsii sebesar 26%. Hasil analisis varians pada taraf 95% menunjukkan tidak ada perbedaan nyata antara perlakuan. Rata-rata persentase penghambatan S. rolfsii oleh Trichoderma spp. masing-masing perlakuan berturut-turut adalah Tc6 = 27,31%, Tc3 = 26,63%, Tc5 = 26,05%, Tc7 = 25,69% dan Tc4 = 24,37%, dengan rata-rata 26,01%. Kata kunci: antagonisme, Trichoderma spp., Sclerotium rolfsii