AbstrakTrace metal sangat penting untuk enzim kofaktor dalam pembentukan metana, namun ketersediaannya secara alami di alam tidak mencukupi sehingga diperlukan penambahan trace metal. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan trace metal Molibdenum (Mo) dan Selenium (Se) sebagai trace metal terhadap kinerja digester anaerobik. Penelitian dilakukan terhadap campuran sampah sayuran, aquadest dan kotoran sapi yang telah diblender kemudian difermentasi selama 30 hari pada variasi penambahan trace metal Mo 10 mg/L, Se 10 mg/L, campuran Mo + Se 10 mg/L di dalam reaktor batch berkapasitas 4 L. Digester dioperasikan pada range pH (6,5 -8) dan suhu lingkungan (25 -30 o C). Pada penelitian ini parameter yang diamati adalah volume bogas, pH, suhu, TS dan VS. Volum kumulatif biogas tertinggi pada penelitian ini sebesar 630 ml dalam reaktor penambahan Mo+Se dengan degradasi TS rata-rata 26,69 % dan VS 17,18 %.Kata kunci: digester anaerobik, kotoran sapi, molibdenum, sampah sayuran, selenium AbstractTrace metal are essential for the enzyme cofactors in methane formation, but its availability of natural is not enough so that the necessary additional trace metal. The purpose of this study is to determine the effect of addition Molybdenum (Mo) and Selenium (Se) as trace metal on the quality and quantity of biogas in anaerobic digesters. The study was carried out by mixing vegetables wastes, aquadest and cow manure that have been in a blender and then have been fermented for 30 days in variety of addition of trace metal Mo 10 mg/L, Se 10 mg/L and a mixture of Mo + Se 10 mg/L in an reactor batch of 4 L capacity. Operation in digesters, pH was maintained in range (6.5 -8) and at temperature 25 -30 o C. This research parameters that observed were volume biogas, pH, temperature, TS and VS. The highest of volume cumulative biogasin this experiment 630 ml are formed Mo + Se, with degradation average TS 26.69 % and VS 17.18 %.