This study was conducted to determine the effect of using white mussel flour fish flour and coconut oil on carcass percentage and abdominal fat percentage in broilers. This study used a completely randomized design consist 4 treatments and 5 replications. The study used DOC ( Day Old Chick ) with the strain Lohman MB 202 Platinum for 20 animals . The treatment in this study was ration without using white mussel flour (P0), ration using 10% white mussel flour (P1), ration using 12.5% white mussel flour (P2), ration using 15% white mussel flour (P3). Variables observed were carcass percentage and abdominal fat percentage. Data were analyzed by Analysis of Variance (ANOVA) if there is a significant effect then proceed with Duncan’s Multiple range test significance level of 5%. The results of the analysis showed that P3 showed a significant difference with the control treatment (P0) and treatment P1 (p<0.05). The best broiler carcass percentage was in treatment P3 (76.02%) and P2 (74.7%) while the lowest was in treatment P0 (71.20%). The results of Duncan's test on the percentage of abdominal fat showed that the control treatment (P0), treatment P1, treatment P2, and treatment P3 were not significantly different (p> 0.05).