In addition to posing a risk for coronary heart disease (CHD), Type A behavior has been suggested as a risk factor for non-CHD illness. Past evidence, however, has relied chiefly on retrospective studies of self-reported illness that failed to control for the potentially confounding effects of negative affectivity. The present investigation was an 18-month prospective study of Type A behavior and medical records of illness in which chronic negative affectivity was also assessed. Negative affectivity was associated with retrospective self-reported illness, but only Type A, as measured by the Jenkins Activity Survey (JAS) and the Framingham Type A Scale (FTAS), predicted medical records of subsequent illness severity and number of illness-related medical visits. Controlling for negative affectivity did not reduce these significant relationships. It was concluded that persons scoring high on the JAS or the FTAS may be a greater risk of minor illness when objective measures of illness are assessed over a period of 1 year or more. Alternative explanations and future directions for research are discussed.