The generation of fat, oil and grease (FOG) waste can be a nuisance hazard, but also a potential for resource recovery. FOG waste can be utilized as nutrient and energy source through anaerobic digestion which may increase methane yield but also increase presence of inhibitors. Using the biochemical methane potential method, this research is aimed to determine the effect of FOG waste in the co-digestion process of food waste (FW) to produce biogas. The research was conducted for 42 days at 37˚C using FOG waste codigested with FW of 3 different volatile solid (VS) rasio which are 0.125, 0.3, and 0.5. The results showed that FOG waste combined with FW has a methane yield that may reach up to 485 ± 36.8 mL CH4/gr VS, the highest one produced by the 0.125 VS rasio mix. While the ratio of FOG waste with FW at 0.3 and 0.5 only produce 128 ± 195 and 4 ± 1.45 mL CH4/gr VS, respectively. The ratio of 0.125 also demonstrates the highest COD reduction of 56% compared to the other ratio which indicates the 0.125 FOG and FW ratio can be implemented to utilize FOG waste and increase methane yield during anaerobic digestion process.