We performed a national survey to determine the prevalence, awareness, treatment and control of hypertension, one of the main cardiovascular risk factors, among the adult population in Tunisia. A total of 8007 adults aged 35-70 years were included in the study. Blood pressure (BP) measurements were taken by physicians with a mercury sphygmomanometer, and standard interviewing procedures were used to record medical history, socio-demographic and cardiovascular disease (CVD) risk factors. Hypertension was defined as a systolic BP ≥140 mm Hg and/or diastolic BP ≥90 mm Hg or current treatment with antihypertensive drugs. The prevalence of hypertension was 30.6%, higher in women (33.5%) than in men (27.3%). Multiple logistic regression analyses identified a higher age, urban area, higher body mass index, type 2 diabetes and family history of CVD as important correlates to the prevalence of hypertension. Only 38.8% of those with hypertension were aware of their diagnosis, of which 84.8% were receiving treatment. BP control was achieved in only 24.1% of treated hypertensive persons. Women were more aware than men (44.8 vs. 28.8%), but the rates of treatment and control of hypertension did not differ between the two genders. Higher age, being female, lower education level and urban area emerged as important correlates of hypertension awareness. The study highlights the hypertension problem in a middle-income developing country. There is an urgent need for a comprehensive integrated population-based intervention program to ameliorate the growing problem of hypertension in Tunisians.