Recent studies have indicated that heightened anxiety and depression in hypertensives, relative to normotensives, is particular to hypertensives' knowledge of their diagnosis. We tested the hypothesis that knowledge of hypertensive diagnosis (KHD) has a stronger association with anxiety and depression for younger than for older individuals. Samples were 239 subjects referred to a hypertension clinic with KHD and 90 subjects, never diagnosed as hypertensive, recruited as a normotensive comparison group. Two age groups, 21-39 and 45-65, were employed. Regression analyses indicated that higher unmedicated blood pressure (BP) values were associated with higher state anxiety but not trait anxiety or depression, after age, education, and sex were entered into the equations. Knowledge of hypertension diagnosis was related to higher scores on all anxiety and depression measures. However, evidence that BP values and KHD had stronger associations with anxiety and depression for a younger than for an older cohort was not obtained. Regression analyses performed within the hypertension clinic referrals indicated that the severity of hypertension as reflected by unmedicated BP values was unrelated to anxiety and depression, and that a history of treatment with anti-hypertensive medications was related only to higher somatic depression.