Registry ascertainment of kindreds with adenomatous polyposis (AP) reduces the incidence of colorectal carcinoma by medical monitoring for offspring and siblings of affected patients. Due to its pleiomorphic genotype and a 50% risk for AP in each patient's progeny, early screening is mandatory. Flexible sigmoidoscopy, averaging from puberty to age 48, annually or every two years, is one diagnostic technique that does not result in excess patient discomfort or cost. Timely examination is facilitated when eye anomalies, osteomas, or epidermoid cysts are present in childhood as potential clinical markers for AP. Denial, misperceptions, and fear may impede surveillance in the absence of education by the registry health care team.