The purpose of this study was to determine the effects of different doses of vitamin E supplemented into the diet on erythrocyte osmotic fragility and some biochemical parameters. Sixty broilers were randomly divided into four groups of 15 each (one control and three experimental groups). Experimental groups (D1, D2, D3) were fed with a diet supplemented with 100, 200 and 300 ppm of vitamin E respectively. The plasma vitamin E level, and other blood parameters, of all the test subjects were measured in the fifth and seventh week of the study. The plasma vitamin E level of D2 and D3 experimental groups in the fifth week, and the plasma vitamin E level of all three experimental groups in the seventh week of the study increased statistically when compared to the control group. Erythrocyte osmotic fragility of all three experimental groups decreased significantly by the fifth and seventh weeks of the study in comparison with the control group, No significant difference in plasma cholesterol, triglyceride, total protein, ALP (alkaline phosphatase), Ca (calcium), P (phosphorus), AST (aspartate aminotransferase) or ALT (alanin aminotransferase) was found between control and experimental groups by the fifth and seventh weeks. Only the ALP level of all groups decreased statistically by the seventh week of the study in comparison to the fifth week.