To determine the prevalence and awareness of hypertension and determinants of blood pressure in rural and urban Sierra Leoneans.598 subjects from Freetown and 606 subjects from three villages in the northern province of Sierra Leone were selected for this study using multi-stage sampling. All were adults aged 15 years and over. Single blood pressure measurements were made after a minimum rest period of 10 minutes using a mercury sphygmomanometer. Korotkoffs phases I and V were used for systolic and diastolic blood pressures, respectively. Standard anthropometric measurements were made and a questionnaire used to collect information on demographic, dietary, and social factors, including consumption of tobacco products, alcohol, salt, palm oil, and kola nuts. Hypertension was diagnosed if systolic blood pressure(SBP) was equal or greater than 160 mm Hg and/or if diastolic blood pressure(DBP) was equal or greater than 95 mm Hg and/or there was a history of hypertensive therapy.The age-adjusted prevalence of hypertension in the Freetown and Port Loko subjects was 23.4% and 14.7%, respectively (P=0.006). Females had a higher prevalence in both populations. The most significant determinants of blood pressure were age, body mass index (BMI) and a low level of education. When adjusted for BMI and age, no significant difference in prevalence was observed between the two populations. The level of awareness was low, particularly in the rural areas.This survey confirms a high prevalence, and low level of awareness, of hypertension in rural and urban Sierra Leoneans.