The diet of the catfish, Clarias buthupogon, was studied in two forest rivers in the Yoko Reserve, the Yoko and Biaro Rivers, from September 2008 to August 2009. Gill nets, long lines and traditional traps were used to catch the fish. An analysis of the contents of 409 stomachs yielded 22 prey Families, 11 Orders and 4 Classes, grouped into 15 major food categories. Indices of weight and volumetric occurrences indicated that Clarias buthupogon eats aquatic insects, crustaceans, oligochaetes, molluscs, animal and plant debris. The average intestinal coefficient was 0.84, which places the species among the insectivorous-prone omnivores. The diet according to sex, season, length and height, and location inside and outside the Yoko Reserve revealed that similar prey items were consumed in similar proportions. The calculated Schöner Index indicates an overlap of diet between seasons and sex.