To investigate racial differences in hypertensive patients' understanding of their disorder, we administered a questionnaire to 83 black and 260 white outpatients with the diagnosis of hypertension designated in their medical chart. No racial differences in systolic or diastolic blood pressure, age, or male/female ratio were observed. However, blacks were more likely than whites to identify renal failure as a consequence of hypertension, whereas whites were more likely to identify atherosclerosis. Blacks also were more likely than whites to accept higher diastolic blood pressures as normal (90 to 100 mm Hg versus 80 to 90 mm Hg). There was no correlation between knowledge and blood pressure. Our observations show that both racial groups are well educated about antihypertensive therapy as well as the consequences and complications of hypertension. Comprehensive treatment of hypertension should include educational strategies that are population-specific and that address ways to change disease-relevant behaviors, rather than merely identifying which behaviors to change.