The first of a two-phase project is reported that examined the prospective effects of stress and social support on the physical and mental health of the elderly. A sample of 50 elderly subjects was assessed at two points in time over a 6-month period. Results indicated that social support was a significant predictor of physical health status, whereas mental health was related to the Stress X Social Support interaction term. These latter results were consistent with the buffering hypothesis, in that high levels of social support served to reduce the negative impact of stress on mental health. Individuals who were in better mental health at the initial assessment experienced fewer stressful events and higher levels of social support over the subsequent 6-month period. The implications of these findings for research and theory regarding the relation between stress and social support are discussed.