An epidemiological study on hypertension was carried out as part of a primary medical care program conducted in the rural areas of the Chaco state (Argentina). The population studied included 473 adults. According to the JNC-VII classification criteria, prevalence of hypertension was 32.3%, prehypertension 34.7%, and normal blood pressure 33%. Gender was not statistically different in the general population or between the subgroups of subjects with hypertension or normal blood pressure. Diabetes was significantly greater among the hypertensive group and smokers were statistically less frequent in the arterial hypertensive group. In the subgroup of patients with a diagnosis of hypertension, 2.5%had criteria for left ventricular hypertrophy (LVH) on the electrocardiogram whereas the eye fundus examination showed that 14%had mild retinopathy and 5%had moderate retinopathy.