Cocoa black pod rot is caused by pathogenic fungi, Phytophtora palmivora, which decrease the cocoa production up to 90%. The use of biological control agents, Trichoderma spp., is one of the promising P. palmivora controllers since it is low-cost, easily found and safe for the environment. The aims of this research were to understand the compatibility, antagonistic and effectiveness of biofungicide containing active ingredient of Trichoderma spp. against P. palmivora in vitro and to test the effective concentration of biofungicide containing active ingredient of T. asperellum to control P. palmivora in vitro and in vivo. T. asperellum, T. harzianum, and T. viride were grown together on PDA medium to test their compatibility. Antagonistic and effectiveness test of Trichoderma spp. against P. palmivora were tested using the in vitro dual culture method. The effectiveness of T. asperellum biofungicide was tested in vivo on cocoa pot. Compatibility test showed that all three species were compatible and the best effectiveness showed by the combination of T. asperellum and T. viride. The result also showed that T. asperellum biofungicide had an ability to inhibit P. palmivora. Keywords: Trichoderma spp., effectivity, compatibility, antagonistic, biofungicide ABSTRAKPenyakit busuk buah kakao disebabkan cendawan patogen Phytophtora palmivora, yang dapat menurunkan produksi kakao sampai 90%. Penggunaan agensia pengendali hayati (APH), Trichoderma spp., merupakan salah satu pengendalian P. palmivora yang menjanjikan karena murah, mudah didapat dan aman terhadap lingkungan. Penelitian ini bertujuan mengetahui kesesuaian, antagonistik, dan efektivitas biofungisida berbahan aktif Trichoderma spp. secara in vitro. Di samping itu juga bertujuan mengetahui konsentrasi efektif biofungisida berbahan aktif T. asperellum untuk mengendalikan P. palmivora secara in vitro dan in vivo. T. asperellum, T. harzianum, dan T. viride, ditumbuhkan bersama pada media PDA untuk mengetahui kesesuaian antarspesies. Antagonistik dan efektivitas Trichoderma spp. terhadap P. palmivora secara in vitro diuji menggunakan metode dual culture. Biofungisida berbahan aktif T. asperellum diuji efektivitasnya secara in vivo pada buah kakao. Hasil uji kesesuaian menunjukkan bahwa ketiga spesies yang diuji berkesesuaian dan efektifitas terbaik ditunjukkan pada kombinasi T. asperellum dan T. viride. Hasil penelitian juga menunjukkan bahwa biofungisida berbahan aktif T. asperellum dengan konsentrasi tertinggi terbukti dapat menghambat pertumbuhan P. palmivora.Kata kunci: Trichoderma spp., efektivitas, kesesuaian, antagonis, biofungisida