The prevalence of hypertension, diabetes and obesity in The Gambia was assessed in a 1% population sample of 6048 adults over 15 years of age, 572 (9.5%) subjects were hypertensive according to WHO criteria (a diastolic blood pressure (DBP) of 95 mmHg or above and/or a systolic blood pressure (SBP) of 160 mmHg or above); 325 (5.4%) had a DBP of 95 mmHg or above, and 39 (2.3%) a DBP of 105 mmHg or above; 428 (7.1%) had a SBP of 160 mmHg or above. By less conservative criteria (a DBP of 90 mmHg or above and/or SBP of 140 mmHg or above), 24.2% of subjects were hypertensive. The prevalence of hypertension was similar in the major ethnic groups and in urban and rural communities. Age and obesity were risk factors for hypertension; female sex was an additional risk factor for diastolic hypertension. Several communities had a prevalence of diastolic hypertension double the national rate, and significant community clustering of diastolic hypertension (P < 0.01) was confirmed by Monte Carlo methods. Genetic and/or localized environmental factors (such as diet or Schistosoma haematobium infection), may be involved 140 (2.3%) subjects were obese. Obesity was associated with female sex, increasing age, urban environment, non-manual work and diastolic hypertension. Only 14 (0.3%) subjects were found to be diabetic. Hypertension appears to be very prevalent in The Gambia, with a substantial population at risk of developing target organ damage. Further studies to delineate this risk and appropriate interventions to reduce it are needed.