Experiments were made to evaluate different combinations of fermented fish-offal meal (FOM) and mulberry leaf meal (MLM) as protein supplement in the formulation of diets for the freshwater catfish, Heteropneustes fossilis. One reference diet (20 % FM) and six experimental diets containing either mixture of fermented FOM (20-30 %) and MLM (24-35 %) or MLM alone (65-80 %) partially replacing FM were formulated. A ten days digestibility experiment and a sixty days growth experiment with these diets exhibited that the diet with 30 % FOM, 5 % FM and 24 % MLM, replacing 75 % of FM, rendered best growth of the H. fossilis. Deposition of crude protein and lipid in the whole body was also significantly higher in this diet as compared to the reference diet. It was concluded that effectiveness of fermented FOM in replacing FM could be substantially increased by limited inclusion of MLM in the formulation of diet for H. fossilis.