One hundred twenty patients with primary retrorectal tumors (79 congenital, 14 neurogenic, 13 osseous, and 14 miscellaneous) had their initial treatment at the Mayo Clinic from 1960 to 1979. The mean age was 43 years (100 patients were adults). Female predominance was associated with congenital cysts (15:1) and male predominance with chordomas (5:1). Forty-three percent of the patients had malignant lesions. No dermoid cysts were found in this series. Diagnosis was made by digital examination or sacral radiographs in all patients. Computed tomography scan was the most important diagnostic method; the rate of positive findings was 100 percent in 20 patients. Approach to the tumor was posterior in 79 of 102 patients in whom resection was possible. Ten of 66 patients with benign tumors had recurrence. The five-year survival rate for patients with chordomas was 75 percent and for patients with other malignant lesions was 17 percent. Because preoperative biopsy can cause tumor spread, abscess, fecal fistula, or meningitis, it should not be performed if tumors are potentially resectable. Whenever possible, total resection should be done.