Abstract: Nile tilapia (Oreochromis niloticus) fingerlings (Average weight 34.50 ± 0.05g) were cultured in glass aquaria and fed two formulated (pelleted) diets for 12 weeks. The control diet containing wheat bran replaced with 30% olive mill waste. Each diet was fed to 3 groups of 15 fish / aquarium. At the end of the trial, growth performance and biochemical parameters values of serum glucose, total protein, cholesterol, triglyceride, and serum enzymes, aspartate aminotransferase (AST) and alanine aminotransferase(ALT) were measured. Results indicated, no significant (P<0.05) differences in average body weight, protein efficiency ratio and the survival rate between fish fed on treated and control diets, while there was significant differences in standard growth rate and feed conversion ratio. Additionally, the blood serum of glucose, total protein, and cholesterol were lower in the treated than the control group. While the values of triglycerides of fish fed on treated diet was twice that found in fish fed on control diets. For the serum enzymes (AST and ALT ) evaluated in this experimental caused no significant differences in both groups of fish.The mean values of these biochemical parameters were within the acceptable range for normal metabolism of Nile tilapia. The results of this study seem to indicate that olive mill waste improved its nutritional value in practical feeds for Nile tilapia fingerlings and without any effect on biochemical parameters.