This study sought to clarify the relationship between cardiovascular reactivity, hostility, depression and ethnicity. Blood pressure and heart rate responses to a standard arithmetic stressor were analyzed in 97 unmedicated hypertensive and normotensive men. Hypertensives and normotensives showed similar increases from baseline on systolic and diastolic blood pressure and on heart rate. Among whites (N = 44), systolic and diastolic reactivity were related to lower scores on the Verbal subscale items of the Buss-Durkee Hostility Inventory (p less than 0.05, for both). Among blacks (N = 53), no such relationship was found. Heart rate reactivity was related to greater depression scores among whites (p less than 0.01), but not among blacks. Among black subjects, heart rate increases were related to higher scores on the Indirect Anger subscale items of the Buss-Durkee (p less than 0.05). These results suggest that the expression of emotion and reactivity to a psychosocial stressor may be socioculturally mediated.