Gastrointestinal lipomas are rare, but commonest in the colon and rectum, characteristically submucosal and seldom subserosal. An 18-year analysis revealed 17 cases of large-bowel lipoma, 13 presenting with colicky pain, abdominal discomfort, blood-stained feces or rectal bleeding and altered bowel habits and four asymptomatic. The 17 patients had totally 21 lipomas, all submucosal. No patients with multiple lipoma had evidence of lipoma at other sites. The ileocecal valve and cecum were most commonly affected, followed by the rectum, sigmoid colon and descending colon. Tumor size (largest diameter) was 0.5-10 cm, averaging 3.1 cm (3.5 cm in symptomatic, and 1.8 cm in asymptomatic patients). The primary diagnosis (with barium enema, colonoscopy and CT) was lipoma in only five cases, but CT gave the correct diagnosis in all three cases in which it was used. Two lipomas were found in surgical specimens from colorectal malignancy, while nine were misinterpreted as polyps and one as angiodysplasia. In symptomatic patients unnecessary colotomy or colonic resection may be avoidable by colonscopic removal of lipoma.