In a 9-week feeding experiment, 270 day-old broiler chicks were fed four dried fish silage-based diets as a substitute for fish meal. Optimum growth and feed efficiency were obtained with fish meal and neutral maize-fish silage diets. The acidic maize-fish silage and acidic cassava-fish silage diets gave the poorest performance and the highest ( P < 0·05) percentage mortality. Nitrogen- and lipid-retention values were significantly ( P < 0·5) influenced by dietary treatments. Metabolizable energy increased for fish meal but was uniformly low in all fish silage-based diets. The substitution of fish meal by fish silage also significantly reduced broiler carcass quality. Total edible meat, breast cuts and weights of giblets of fish meal and neutral maize-fish silage diets were not significantly different, but dressed and eviscerated carcass weights were significantly ( P < 0·05) highest in fish meal diets and lowest in acidic maize-fish silage and acidic cassava-fish silage diets. Costs of feed per kilogram diet and per kilogram body weight gain were only slightly reduced when fish silage substituted fish meal in broiler feed formulation.