Because of the persistent shortage of health care resources, scientists and politicians are discussing ways to increase the patients' personal responsibility for their own health. Based on a philosophical analysis of the concept of responsibility, this article tries to assess strengths and limits of a personal responsibility for health, illustrated by the prevention of cutaneous melanoma. On the one hand, individuals bear prospective responsibility for their health status by adopting a healthy lifestyle and participating in prevention programs. On the other hand, individuals can--retrospectively--be held responsible for those conditions that result from the voluntary choice of health risks. Considering the tremendous practical and ethical problems associated with retrospective responsibility, prevention and public health policies should emphasize prospective personal responsibility for health.