This study evaluated the influence of diets supplemented with 0, 80, 160, 240 mg kg−1 (E0, E80, E160, E240) of vitamin E on the physiological responses of Nile tilapia (Oreochromis niloticus) fed for 3 months. Weight were not affected by dietary vitamin E concentrations. An increase (p<0.05) on the red blood cells count and on the hemoglobin concentration was obtained on treatments with 80 and 160 mg vitamin E kg−1 relativeto control. Mean corpuscular volume presented a significant increase (p<0.05) on treatment with 240 mg vitamin E kg−1 when compared to control. Mean corpuscular hemoglobin concentration was significantly decreased (p<0.05) on treatment with 240 mg vitamin E kg−1. The vitamin E treatments, we noticed a significant increase (p<0.05) in the number of leucocytes relative to control.  Our results suggest that 80 mg vitamin E kg−1 is probably the most suitable concentrations for Tilapia diets, although high vitamin E diets are necessary for quantitative leucocyte increases for tilapia