Targeted screening by colonoscopy of asymptomatic first-degree relatives of patients with colorectal cancer (CRC) is promoted as a preventive health activity. This retrospective case control series details the results of this activity in a community-based referral gastroenterology practice. One advanced carcinoma and 22 adenomas in 15 patients were found in 118 individuals screened. Six per cent of those screened had advanced lesions (carcinoma, tubulovillous adenomas or adenomas larger than 1 cm). Colonoscopic screening of asymptomatic first-degree relatives of patients with CRC yields a limited number of clinically significant colonic neoplasms in this practice setting. Further cost-benefit data are needed.