The pathogenesis of chronic hepatitis C (HCV) infection is not fully known, but oxidative stress may play a role. The aim of this study was to assess the relationship between HCV load and antioxidant status among patients with chronic HCV infection. Among 23 patients, HCV load, as well as plasma beta-carotene, retinol, ascorbic acid and alpha-tocopherol were measured. Plasma retinol, ascorbic acid and alpha-tocopherol were low in 17%, 26% and 4% of the patients, respectively. Plasma ascorbic acid and alpha-tocopherol declined 9.7 micromol/l (95% CI 3.3-16.2) and 4.5 micromol/l (95% CI 2.1-7.0), respectively, and plasma beta-carotene declined by a factor of 0.60 (95% CI 0.37-0.98) per log increase in viral load. Smoking was independently associated with 8.9 micromol/l (95% CI 4.1-13.7), lower levels of plasma alpha-tocopherol and with 0.27 (95% CI 0.11-0.71) times lower plasma beta-carotene. The effect on plasma ascorbic acid was not significant (-9.2 micromol/l, 95% CI - 21.9-3.5). The association may reflect consumption of antioxidants due to HCV, although effects of low antioxidant status on viral replication cannot be excluded.