Twenty-two cases of intravenous leiomyomatosis (IVL) of the uterus were examined at the Royal Women's Hospital, Melbourne, within a 22-year period. The mean age of the patients was 46 years (range, 23-66). Nine patients presented with a pelvic mass, nine with abnormal uterine bleeding, and one with prolapse of the uterus. In three cases, the presenting features were unknown. Surgical exploration confirmed the presence of a uterine mass (mean size, 7.8 cm) which in seven cases extended into the broad ligament. In only 11 cases was involvement of the myometrial vessels obvious on gross examination. However, no extension into the iliac veins or inferior vena cava was found. In seven cases, the tumor involved to a minimal degree the immediately adjacent or contiguous myometrial veins, and the diagnosis of IVL was made incidentally on microscropic examination. Of the 16 patients with follow-up (mean, 7.5 years) all are now disease free. Five years after the diagnosis of IVL, one patient (case 10) had a pulmonary smooth-muscle tumor resected. All 22 patients were treated by surgery alone, and to date none have died from disease. Our findings support the benign biologic behavior of IVL even in the presence of metastases.