OUTLINE: Data is collected on patients and their families for inclusion in a hereditary colorectal cancer registry. Registry data is entered into a secure database that includes information on patient demographics and medical and family cancer history. The information collected will be used to formulate screening and surveillance recommendations, to further knowledge of hereditary colorectal cancer, and to facilitate cancer research. Registry data will also be used to improve the quality of current standard of care through timely tracking and notification of patients for follow-up care, identification of registry participants at high risk for developing an inherited form of colon cancer, and by serving as a resource for future research.