This study proposes to identify factors influencing decision-making regarding genetic testing for Hereditary Nonpolyposis Colorectal Cancer (HNPCC) and the psychological and behavioral outcomes of the testing process. HNPCC is an inherited form of cancer that predisposes persons in such families to multiple kinds of cancer, most notably colon and endometrial cancer. Biological relatives in families with a known HNPCC mutation complete a baseline questionnaire assessing knowledge, expectations, mood, attitudes, perceived cancer risk, cancer worries, family relationships, spirituality, coping and health beliefs. Participants are then provided with an educational/counseling session focused on HNPCC, the availability of genetic testing, its risks, limitations and potential benefits, and cancer screening recommendations for families with HNPCC. Participants are then presented with a choice of whether or not to undergo genetic testing. Those choosing genetic testing undergo a separate informed consent specifically focused on the process of genetic testing and the potential risks, benefits and limitations of genetic testing. Psychological and behavioral outcomes are reassessed through telephone questionnaire at 6 months, 1 and 3 years following risk notification or the decision not to undergo testing. For those receiving genetic test results, notification occurs in person along with discussion of available surveillance options. Follow-up counseling and support are provided for all individuals participating in the study. To date, 383 individuals have completed baseline questionnaires, 314 individuals have completed 6- month follow-up questionnaires, and 278 have completed 1 year questionnaires; 3 year follow-up surveys are being initiated.