The purpose of this study was to examine variations in individual approaches to human relationships among members of a cohort of healthy medical students as revealed by their Rorschach Tests, and to explore the association between the assessed youthful relationship potential and midlife health or illness. In particular, the relationship potential among future cancer victims was found to differ significantly form that of their fellow students who remained healthy or who developed a cardiovascular disorder, but resembled that of those men who later became mentally ill or committed suicide. These prospective findings appear to fit with several retrospective reports stressing the role of human relationships as a psychological factor in the development of cancer.