Basic and medical science investigations have identified a growing number of risk factors important in carcinogenesis. By communicating cancer risk information in medical practice, we have the potential to motivate high-risk individuals to adhere to cancer prevention and surveillance protocols. However, cancer screening and risk notification might have adverse psychologic and social consequences as well. In this review, we address the psychosocial and ethical implications of cancer risk notification. The literature on the psychosocial impact of cancer screening programs and programs for notifying workers exposed to occupational carcinogens is reviewed critically. In addition, we examine new concerns and responsibilities raised by the emerging field of cancer genetics. Suggestions for future research and for patient education are addressed.