Cardiovascular responses to psychological events may mediate the influence of stress on cardiovascular disease. In this study the authors asked whether cardiovascular responses to psychological challenge changed with age and whether such changes were intrinsic to aging or could be attributed to the influence of disease and medications. Cardiovascular reactivity to mental challenge was examined in 902 men ranging in age from 46 to 64 years who participated in the Kuopio Ischemic Heart Disease Risk Factor Study. A battery of 4 tasks was used to induce cardiovascular responses. Current disease status, age, and medication use were entered into hierarchical regression analyses to assess their relation with measures of cardiovascular reactivity. Age and hypertension contribute;l independent, approximately equal, but small amounts of variance in the cardiac and vascular reactivity indexes. Medications also influenced reactivity independently of age and disease. Performance on the tasks was more consistently altered by age than by disease or medication. Cardiac and vascular reactivity increased with increasing age and the presence of hypertension. The authors conclude that both age and disease state must be considered when examining cardiovascular reactivity as a risk factor for disease.