A feeding trial was performed to investigate levels of corn-based Distillers Dried Grains with solubles (DDGS), a co-product of fuel ethanol manufacturing, used as a nutrient source for juvenile Nile tilapia (Oreochromis niloticus). Three isocaloric (15.7±0.7 MJ kg-1 dry matter), isonitrogenous (29.6±1.0% crude protein) experimental diets were formulated to contain 20, 30 and 40% DDGS; a commercial diet containing fishmeal was used as a reference diet. Glass aquaria (110 L) were stocked with Nile tilapia (mean weight = 6.7 g) with four replicates per diet. Weight gains, conversion ratios and hepatosomatic indices did not significantly differ between fish fed 20% DDGS and reference diets. Dressing percentages were similar among fish fed 20 and 30% DDGS and reference diets, while no difference occurred in protein efficiency ratios among diets. These results indicate that aquaculture diets incorporating 20% DDGS may produce similar performance results to commercial diets of similar energy content.