OBJECTIVE: To investigate the distribution of obesity and its association with pre-adult wealth and adult socio-economic factors in urban Ghanaian civil servants. STUDY DESIGN: Cross-sectional study of urban civil servants. METHODS: A total of 1015 (615 men and 400 women) civil servants aged 25 years and above employed in seven central government ministries and departments in Accra, Ghana were studied (participation rate 82.7%). RESULTS: The prevalence of obesity [body mass index (BMI) > or =30.0 kg/m(2)] was 10% in men and 36% in women. Men of higher pre-adult or current socio-economic position generally had higher mean BMI and waist circumference. In women, however, the mean waist circumference was higher in those of lower socio-economic position (lower education, less pre-adult wealth), but mean BMI did not differ significantly between socio-economic groups. There was a positive graded association between pre-adult and adult levels of wealth (determined by the availability of selected household amenities) and the risk of obesity in men (P-trend=0.003), but weak suggestions of an inverse association between adult level of wealth and obesity in women under 45 years of age. CONCLUSIONS: The high prevalence of obesity in this population indicates the need for appropriate interventions for its prevention and treatment. Programmes and interventions to control obesity need to address different needs of men and women in the various social strata, and must not be limited to adults.