In three patients aged 21 to 65 rectal polyps diagnosed at rectoscopy were removed by diathermy loop. Histology showed them to be carcinoid tumours, one of tubular type, two of mixed type. Rectal carcinoid rarely presents with typical clinical symptoms. Polyps discovered by digital examination or rectoscopy should be considered to be potentially malignant and removed in toto. The size of the tumour is of decisive prognostic importance. Tumours with a cross section over 2 cm should be treated as malignant. The histological investigation generally gives no indication of clinical prognosis or of the possibility of metastases. Despite invasive growth and despite local or distant metastases carcinoid tumours can be judged more favourably than carcinoma. The plan of treatment should be according to the clinical findings as well, and not only to histological results. Postoperative follow-up is considered imperative.