The present study evaluated the prevalence of hypertension (HT) and its possible relationships with various risk factors in a representative sample (n=2884) of the adult population (>18 years old) of Galicia, a region of Spain. Subjects were selected by a two-step cluster sampling procedure from the Galician public health service database, which covers more than 95% of the population (2.7 million inhabitants). The overall prevalence of HT, defined as BP >140/90 mm Hg and/or current treatment with antihypertensive medication, was 25.5%, higher in men (31.1%) than in women (20.7%). Of the hypertensive subjects 50.6% were aware of the HT; of these, 72.0% were receiving treatment and 36.4% were treated and controlled. The prevalence of HT increased with age and was higher in subjects from urban areas than rural areas and higher in subjects with low educational level. Surprisingly, people with low educational level more frequently showed awareness of HT than people with high education level. Increased body mass index was related to increased prevalence of HT and close associations were observed between HT and cardiovascular diseases. Our data also show a linear upward trend in blood pressure from normal glucose metabolism to diabetes mellitus. Surprisingly, the prevalence of HT among people with known diabetes was higher than among people with undetected diabetes, which may indicate poor control of HT in diabetic subjects.