To analyze the health disparities relative to the prevalence of arterial hypertension and its therapeutic control in the active French population, in relation to occupational categories (OC), a population of 17 359 men and 12 267 women was assessed from January 1997 to April 1998. The initial phase was a cross-sectional analysis of a cohort study designed to assess the incidence of arterial hypertension in a French working population. Information was collected by the worksite physician during the annual examination. Blood pressure (BP) was measured using a validated automatic device. Among subjects with a BP > or =140/90 mm Hg, patients not treated with antihypertensive drugs were invited to have an additional BP measurement, 1 month later. Overall prevalence was 16.1% for men and 9.4% for women. Both prevalence and therapeutic control of high BP were related to OCs in this study. Prevalence of hypertension was higher and maintenance of therapeutic control lower among lower OCs. In contrast, awareness of high BP and the proportion of hypertensive subjects under current treatment were not related to OCs. Educational level and low OC were significantly related to prevalence of high BP after adjustment for obesity, excessive alcohol consumption, and sedentary lifestyle in women only. A poor BP control under treatment was related to high alcohol intake and low OC in men. In women only, however, low educational level was related to high prevalence of hypertension and poor BP control under antihypertensive treatment. Inequalities in hypertension prevalence persist, with prevalence being higher among lower OCs. Social disparities were not observed, however, in awareness of their condition among hypertensive subjects and among patients for receiving versus not receiving any treatment for hypertension. In contrast, BP control under antihypertensive treatment was lower among lower OCs.