Abstrak. Penelitian ini bertujuan untuk mengetahui kemampuan rizobakteri isolat tanaman kakao dalam menghambat pertumbuhan koloni Phytophtora palmivora penyebab busuk buah kakao dan menginduksi ketahanan sistemik serta pengaruhnya terhadap peningkatan viabilitas dan vigor benih kakao. Penelitian dilaksanakan di Laboratorium Ilmu dan Teknologi Benih Jurusan Agroteknologi, Fakultas Pertanian, Universitas Syiah Kuala, Darussalam Banda Aceh. Pelaksanaan penelitian dilaksanakan dari bulan Februari sampai April 2019. Rancangan Acak Lengkap non faktorial. Faktor yang diteliti dalam penelitian ini adalah perbedaan isolat rizobakteri dalam menghambat Phytophthora palmivora dan uji induksi ketahanan sistemik serta viabilitas dan vigor benih kakao yang terdiri dari 15 isolat rizobakteri. Setiap taraf percobaan diulang tiga kali, yang diuji lanjut dengan uji Beda Nyata Jujur (BNJ) dan pada parameter perlakuan benih menggunakan rizobakteri terhadap viabilitas dan vigor benih kakao menggunakan uji Duncun Multiple Range Test (DMRT) pada taraf 5%. Hasil penelitian menunjukkan bahwa isolat yang memiliki persentase daya hambat terbaik yaitu isolat GM 8/8 penghambatan 51,12% yang termasuk dalam kategori penghambatan sedang (51-60% DH). Pada uji daya larut fosfat terdapat tiga isolat rizobakteri yang mampu dalam melarutkan fosfat, yaitu GM 7/10, GM 8/1 dan GM 8/2. Aktivitas peroksidase tertinggi ditunjukkan pada perlakuan benih dengan agen biokontrol GM 8/2 yaitu 4,17 U/mg protein. Sedangkan perlakuan benih menggunakan rizobakteri berpengaruh sangat nyata pada tolok ukur DB, IV, KST, KCT-R, T50 rizobakteri isolat GM 8/9. Kata kunci: Kakao, patogen, rizobakteri, viabilitas dan vigor. This study aims to determine the rizobacterial ability of cocoa isolates to inhibit the growth of Phytophtora palmivora colonies that cause cocoa pod rot and induce systemic resistance and its effect on increasing the viability and vigor of cocoa seeds. The study was conducted at the Seed Science and Technology Laboratory of the Department of Agrotechnology, Faculty of Agriculture, Syiah Kuala University, Banda Aceh. The research was carried out from February to April 2019. The non factorial Complete Randomized Design. The factors examined in this study were differences in rhizobacterial isolates in inhibiting Phytophthora palmivora and induction test for systemic endurance and viability and vigor of cocoa seeds consisting of 15 rizobacterial isolates. Each trial level was repeated three times, which was further tested with the Honestly Significant Difference (BNJ) test and in the parameters of seed treatment using rizobacteria on the viability and vigor of cocoa seeds using the Duncun Multiple Range Test (DMRT) at 5% level. The results showed that the isolate which had the best percentage of inhibition was GM 8/8 inhibitory 51.12% which was included in the category of moderate inhibition (51-60% DH). In the phosphate solubility test there are three isolates of rhizobacteria that are able to dissolve phosphate, namely GM 7/10, GM 8/1 and GM 8/2. The highest peroxidase activity was demonstrated in seed treatment with a GM 8/2 biocontrol agent, 4.17 U / mg protein. While the treatment of seed using rhizobacteria has a very significant effect on the DB, IV, KST, KCT-R, T50 benchmarks rizobacteria isolate GM 8/9. Keywords: Cocoa, pathogen, rhizobacteria, viability and vigor.