Background. Exercise has significant affects on free radical production. Objective. The objective of the present study was to explore the effect of vitamin C supplementation on lipid peroxidation and lactate levels in sedentary individuals who performed exhaustion exercised. Methods. 10 healthy sedentary male athletes participated to study. They were supplemented with 300 mg oral vitamin C (L-ascorbic acid, Ester-C Plus 500 mg, Solgar-USA) and subjected to acute exhaustion exercise by fatigue developed one time a week for 4 weeks. Exhaustion exercises were carried out until exhaustion developed according to Bruce protocol once a week for 4 weeks. Blood samples were collected from the subjects four times, at the beginning and at the end of the supplementation and before and after exercise, over the 4-weeks study period. The samples were used to analyze MDA, GSH, GSH-Px, CAT, SOD and NO levels by using ELISA colorimetric method and plasma lactate levels by an autoanalyzer device. Results. Exhaustion MDA, GSH, GSH-Px, CAT, SOD and NO levels measured both before and after supplementation were higher than resting levels (p<0.05). MDA, NO and lactate levels that were elevated in exhaustion before supplementation decreased significantly after vitamin C supplementation (p<0.05). Conclusion. The results of our study indicate that the increase in free radical production and lactate levels due to by 4-week exhaustion exercise were offset by vitamin C supplementation. It can be argued in conclusion that supplementation of physiologic doses of vitamin C may be useful for athlete health and performance.