Personality characteristics such as anxiety and anger have long been associated with essential hypertension, but the results of past studies have often been confounded by inadequate diagnosis of hypertension, antihypertensive medications, and use of unvalidated measures of personality. Moreover, little attention has been given to the importance of differential exposure to medical attention and labeling as determinants of personality. To overcome these shortcomings, personality characteristics were measured by self-report using validated questionnaires in untreated male and female hypertensives who were either aware (n = 80) or unaware (n = 82) of their hypertension at the time of assessment. Hypertension diagnosis was based upon repeated blood pressure measurements over 5 months. Hypertensives were compared to age-, sex-, ethnicity-, and occupation-matched normotensives. Results indicated that aware hypertensives scored significantly higher than normotensives and unaware hypertensives on neuroticism, trait and state anxiety, and self-reported Type A behavior. They also scored higher than normotensives on state anger, and there was a similar trend for anger suppression. There were no differences between unaware hypertensives and normotensives. The findings suggest that these personality factors are not a fundamental characteristic of hypertension but reflect the influence of exposure to medical attention or knowledge of hypertension status.