BACKGROUND: In many parts of the developing world, modernization has resulted in an increase in the prevalence of overweight and obesity and a subsequent rise in nutrition-related, non-communicable diseases such as cardiovascular disease and Type 2 diabetes. AIM: The study examined the impact of socio-economic and lifestyle changes associated with modernization on the body size and shape of Balinese women. SUBJECTS AND METHODS: Anthropometric data including weight, height, body mass index (BMI) and seven skinfolds were collected from 564 Balinese women, aged between 15 and 45 years. The relationship between the degree of 'modernization' (using such parameters as household wealth and education level) and body size and shape was analysed using multiple regression analysis, as was the effect of age, family size and breast-feeding. RESULTS: Using the WHO (WHO 1995) categories of BMI, 14% of Balinese women displayed Chronic Energy Deficiency (BMI < 18.5 kg m(-2)), 7% were overweight (BMI = 25.0-29.9 kg m(-2)) and less than 1% were obese (BMI > or = 30.0 kg m(-2)). Household wealth (p < 0.0001) and education level (p < 0.05) were significantly associated with fatness, while breast-feeding (p < 0.05) was significantly associated with leanness. Fat distribution was largely independent of biological and socio-economic variables. CONCLUSIONS: The trend toward increasing fatness associated with greater household wealth and higher education has important health implications for Balinese women as they continue their rapid transition from subsistence agriculture towards a more 'western' lifestyle.