A feeding trial was carried out to investigate the effects of dietary fermented distillers dried grains (FDDGs) on the growth performance, feed efficiency, body chemical composition, blood biochemical tests and economic evaluation of the Nile tilapia, Oreochromis niloticus fingerlings. Distillers dried grains were subjected to solid-state fermentation then incorporated into four experimental (Iso-nitrogenous 30% and iso-Calroric 4400Kcal/Kg) diets containing 0, 25, 50 and 75% FDDGs instead of soybean meal. Results revealed that bioprocessing increases the protein content of DDGs. All growth performance parameters (BW, WG, RGR, DWG, and SGR) demonstrated significant increase with low substitution levels (25 and 50% FDDGs). Survival rate and feed consumption did not differ between all treatments. Feed conversion ratio (FCR), feed efficiency ratio (FER), and protein efficiency ratio (PER) showed significant improvements with low substitution levels (25 and 50% FDDGs). Body dry matter, protein and ash contents did not differ significantly with the control, however, both fat and energy content showed a significant increase for all substitution levels. These results indicate that incorporation of FDDGs meal into tilapia diets at 25 and 50% levels were the best in terms of growth performance, feed utilization and economic evaluation under these experimental conditions.