Objective: To assess the relation between specific flavonoid classes and peripheral arterial occlusive disease (PAOD), an important manifestation of atherosclerosis. Design: Using data from a case-control study conducted in Greece in 1980 on the nutritional epidemiology of PAOD, we have exploited recently published databases on the content of foods in specific flavonoid classes to assess the relation between intake of these compounds and PAOD. Setting: A major teaching hospital in Athens, Greece. Subjects: Cases were 100 patients with PAOD and controls 100 patients with minor surgical conditions admitted to the same hospital. Interventions: No interventions. All cases and controls were interviewed in the hospital wards, and a 110-food item semiquantitative food frequency questionnaire was administered by the same interviewer. Results: Flavonols, flavones and perhaps flavan-3-ols were inversely associated with PAOD risk, the odds ratios (and 95% confidence intervals) for increments equal to the corresponding standard deviations being 0.41 (0.20-0.86), 0.56 (0.32-0.96) and 0.53 (0.26-1.05), respectively. Total flavonoids were also significantly inversely associated with PAOD. Conclusions: On the basis of these results, the biological properties of flavonoids and evidence concerning their relation to other manifestations of atherosclerosis, we conclude that dietary intake of specific classes of flavonoids, as well as total flavonoids, may have a protective effect against PAOD.