Genetic counseling may turn risk information into cancer prevention behavior by modifying health beliefs and cancer-related distress. We assessed the effect of genetic counseling on these factors in 101 adult first-degree-relatives of colorectal cancer patients from families with known or suspected hereditary nonpolyposis colorectal cancer. Before counseling and once afterward, subjects completed self-report measures of perceived lifetime risk and cancer-distress. Most persons overestimated their cancer risk, and higher perceived risk was associated with believing that colorectal cancer cannot be prevented. Individual perceived risk changed after counseling, although mean perceived risk was unchanged. After adjusting for baseline risk, older persons and those with higher estimated objective cancer risk had larger postcounseling decreases. Distress after counseling was positively correlated with baseline distress and anxiety symptoms, and inversely correlated with tolerance for ambiguity. The findings suggest counseling interventions that should increase the likelihood of screening and offer hypotheses for future research.