Exercise increases oxygen consumption and causes a disturbance of intracellular pro-oxidant-antioxidant homeostasis. Athletes are exposed to acute and chronic stress that may lead to increased generation of oxidative species. Hence oxidative stress increases in athletes. Administration of antioxidant like alpha-tocopherol as supplementation may reduce the cell damage caused due to oxidative stress. In the present study, our aim was to study the effects of alpha-tocopherol supplementation on the cardiopulmonary fitness in endurance athletes (cyclists) and non-athletes. Our study included 40 cyclists who were trained under District Youth Service & Sports Office. 40 controls were randomly selected from student group of B.L.D.E.A's Medical College. Alpha-tocopherol (Vitamin E) 200 mg/day for 21 days wasgiven to study group and placebo was given to placebo group. Various physiological parameters like heart rate, blood pressure, respiratory rate were recorded, for assessing cardiopulmonary fitness: Physical Fitness Index (PFI) and VO2 max ml/min/kg were recorded before and after supplementation of vitamin E in athletes, and were compared with placebo group before and after supplementation of placebo and also with non-athletes. The results obtained from present study indicate that antioxidant like alpha-tocopherol supplementation did not contribute significantly to improve the cardiopulmonary fitness of endurance athletes.