Personality hardiness is purported to have a buffering effect on the debilitating consequences of life stresses, such as physical illness. Cardiovascular reactivity as measured by increases in heart rate, systolic blood pressure, and diastolic blood pressure has been implicated in the development of coronary heart disease and established hypertension. Using a mental arithmetic task to stimulate active coping conditions, this study examined the relationship between hardiness and cardiovascular reactivity in 55 males aged 22 to 51 years old, especially whether high hardiness served as a buffer of heart rate, systolic blood pressure, and/or diastolic blood pressure reactivity. Global hardiness was not significantly related to cardiovascular reactivity, and a component of hardiness (commitment) was found to have a significant, positive relationship with systolic blood pressure when type A behavior pattern, age, and parental history of hypertension were held constant.