Age-related macular degeneration (ARMD) may result from events initiated by reactive oxygen species. Blood samples from 18 patients with ARMD and 18 similarly aged controls were analysed for activities of important antioxidants. Blood glutathione reductase activity was lower in patients with ARMD compared with controls (p=0035). The activities of glutathione peroxidase (p=018) and erythrocyte superoxide dismutase (p=029) were similar between the two groups by a Student's two sample t test. Logistic regression was used to determine which enzyme activities were associated with ARMD after adjusting for possible confounding variables: smoking history, age, multivitamin use, and cardiovascular disease. Glutathione reductase activity (p=0.05) and glutathione peroxidase activity (p=0 065) were significantly associated with ARMD by this analysis. The relation of glutathione reductase and glutathione peroxidase activity to ARMD merits further study.