We have already published much of our data on the seasonal variation of cardiovascular disease risk factors in a cohort of 65-74 year old men and women living in Cambridge, UK. In this paper we give a concise overview of our findings and include previously unpublished data relating to diet. Seasonal variation in intake of fat, copper, beta-carotene and vitamins A, C and E were all found with increased fat, beta-carotene and vitamin A intakes in autumn and winter while vitamin C and E intakes peaked in summer. Seasonal variation of vitamin C intake and serum ascorbate concentrations were particularly pronounced. We postulate that low vitamin C levels in winter could be associated raised plasma fibrinogen and plasminogen activator-1 (PAI-1) concentrations and therefore with increased cardiovascular risk.