The prevalence of diabetes and obesity were assessed in an age- and sex-stratified sample of 1078 individuals living in Mahe, The Republic of Seychelles. Presence or absence of diabetes mellitus was assessed by measuring glucose concentration in fasting venous blood. Prevalence of obesity (standardized for age) was elevated five-fold in women compared with men (20.9 vs 4.2%). In women, it increased from 8.9% at age 25-34 years to 29.4% at age 35-44 years and plateaued thereafter, whereas it did not change with age in men. Prevalence of diabetes (standardized for age) was 3.4% for men and 4.6% for women. It increased markedly with age, from 0.0 and 0.8% at age 25-34 years to 8.8 and 13.4% at age 55-64 years in men and women, respectively. A strong association of diabetes with excess body weight was observed. Most cases of diabetes can be attributed to Type 2 (non-insulin-dependent) diabetes. Fifty-five percent of diabetic individuals were unaware of their disease at the time of the survey.