BACKGROUND: The susceptibility of low-density lipoprotein (LDL) to oxidation is thought to be a crucial factor responsible for atherogenesis. There is substantial evidence for a role of dietary antioxidants in the prevention of atherogenesis and the protective effect of antioxidant nutrients may be mediated through inhibition of the oxidative modification of LDL. METHODS: We performed in vitro oxidation of LDL derived from normal and hypercholesterolemic individuals in absence and presence of different doses of ascorbic acid. RESULTS: The serum lipid peroxidation level was significantly increased in hypercholesterolemic patients and their LDL has shown a greater propensity towards in vitro oxidation. Hypercholesterolemic LDL required a higher amount of ascorbic acid to reduce its oxidation level as compared to LDL isolated from normocholesterolemic individuals. CONCLUSION: This observation may be of importance in designing future studies of antioxidant supplementation in patients with hypercholesterolemia which is one of the major risk factors for atherosclerosis.