We conducted a retrospective cohort study of 751 residents of Rochester, Minnesota, whose small (1 cm or less) colorectal polyps had been treated without biopsy. Eighteen colorectal carcinomas were found in this group in the course of more than 10,000 person-years of follow-up, whereas 15.27 cases were expected (relative risk, 1.2). The overall rate for the development of cancer and the relative risks for various subgroups of the cohort were not significantly elevated, and survival in this cohort was not impaired. We conclude that fulguration of selected small colorectal polyps without prior biopsy does not subject patients to an unusual risk for development of colorectal carcinoma. Customary periodic medical examination should suffice for patients with these lesions.