Data from the Hypertension Detection and Follow-up Program (HDFP), in 14 U.S. communities, were used to examine the relationship of education to the well-documented racial differences in prevalence of hypertension. Standardized blood pressure (BP) measurements, a medical history, and socioeconomic information were obtained on 158,906 adults. Hypertensive individuals were defined as 1) those with a diastolic BP greater than or equal to 95 mm Hg and 2) those with a diastolic BP less than 95 mm Hg who reported they were currently taking antihypertensive medication. Overall, 18.0% of whites and 37.4% of blacks were defined as hypertensive at the first screening. Education was found to be inversely associated with hypertension for each race and sex group. This inverse association remained when age was taken into account, was more striking in the younger age groups and in blacks, but was diminished in the highest weight classes. Educational differences, however, do not fully account for the observed black-white differences in hypertension prevalence. Even at the higher education levels, the adjusted prevalence of hypertension remained nearly twice as high in blacks as in whites.