Objective: To compare, along with behavioural habits, the potential atherogenicity of diets in rural and urban areas in Costa Rica. Design: Subjects (n= 503) were randomly selected from the general population in Costa Rica. A validated food-frequency questionnaire that inquired about dietary intake in the previous year was administered once to each subject. Each subject provided plasma and an adipose tissue biopsy, which were used as biomarkers for carotenoid, tocopherol and/or fatty acid intakes. Each subject also answered another questionnaire on personal profile and household characteristics. Setting: A dietitian visited all subjects and conducted the interviews at their homes. Subjects: Adult male and female free-living rural, suburban and urban Costa Ricans without a history of physical or mental disability. Results: Subjects in rural areas were significantly (P<0,05) more active physically, earned less income and had a higher intake of dietary fibre than urban dwellers. Urban residents reported a significantly (P< 0.05) higher consumption of total fat, specifically unsaturated fat mostly from soyabean oil, and had higher plasma and adipose tissue tocopherol and lycopene concentrations. Interestingly, no differences in body mass index were observed. Conclusions: These data show differences in cardiovascular disease (CVD) risk factors of rural and urban populations in Costa Rica. In rural areas, low socio-economic status and low intake of unsaturated fatty acids appear to be the prevalent CVD risk factors, while in urban areas they were low physical activity, high trans-fatty acids in the diet and adipose tissue, and low dietary fibre intake.