Polypoid tumours of the small and large intestine have been recognized as a complication of the implantation of ureters into the bowel for many years. Some cases could be recurrences of the urothelial tumour which necessitated the original operation or alternatively others may be tumours arising from the bowel epithelium itself. Malignant and benign varieties of such bowel tumours have been reported, although the description of some of the latter have suggested that they were not true tumours but some variety of 'polyp'. We describe here two polyps arising in the colon some 22 years after ureterosigmoidostomy and discuss the probably mixed nature with elements of both juvenile polyp and tubular adenoma.