Ash content significantly differed with fish weight only. The optimum feed conversion ratio (FCR) was obtained with fry tilapia fed the 45%-CP diet; whereas, the poorest FCR was observed for advanced juveniles fed the 25%-CP diet. The lowest PER and Productive value (PPV) values were obtained with the 45%-CP dietfed to advanced juveniles; whereas, the highest values were obtained with the 25%-CP diet fad to fry. The highest porttein growth rate (PGR) was obtained with fry the 45%-CP diet, which the lowest onewas obtained with advanced juvenile fed the 25%-CP diet. Hemaatological variables were significantly affected by protein level, fish weight, and their interaction except for serum lipids which was not significantly affected by the interaction. Activities of aspartate amninotransferase (AST) and alanine aminotransferase (ALT) in serum, liver, and muscles were significantly affected by dietary protein level and fish weigth. The interaction significantly affected enzyme activities exce pt for serum AST, which was not significant.