Colonoscopy and endoscopic polypectomy are being utilized more frequently these days with the increased emphasis on the prevention, early detection, and treatment of colon cancer. Consequently, the problem of managing the malignant polyp is likely to be more frequently encountered. Many attempts have been made to clarify the management principles involved. Although the studies conducted have been imperfect in their design, the variety of information obtained from these studies is making the picture clearer. A more conservative approach is evolving. Many malignant polyps may be managed by endoscopic polypectomy alone. The criteria for which patients are to be managed in this fashion seem to be relatively simple ones, though technical problems with polypectomy performance and histologic evaluation are still frequently encountered. More carefully designed long-term studies are needed to create firm guidelines for the management of malignant polyps. Should screening and surveillance result in the discovery of earlier and more readily treatable forms of invasive colon cancer, endoscopic polypectomy will most certainly be a cornerstone of their treatment.