Experience in the treatment of 118 patients with nonepithelial new growths of the rectum has been accumulated at the Scientific Research Institute of Proctology in the period from 1970 to 1991. They accounted for 1.5% of all benign and malignant tumors of this organ. Leiomyoma was diagnosed in 44, leiomyosarcoma in 18, lipoma in 30, fibroma in 17, neurinoma in 7 and rhabdomyoma in 2 of these patients. A differential diagnosis was made between benign and malignant tumors, as well as with other nonepithelial new growth of the rectum. On the basis of the clinical picture and the results of digital and instrumental (radiological, endoscopic, and ultrasonic) examination of the rectum the correct preoperative diagnosis may be established with certain probability. This influences directly the choice of the volume of the operative intervention in various types of nonepithelial rectal tumors. Morphological verification of the tumor is the principal method of examination in establishing the differential diagnosis in the preoperative and postoperative periods.