Ovarian transposition in adults has been shown to protect ovarian function in about 60% of cases by reducing ovarian exposure to less than 4 to 7 Gy. We therefore evaluated the effect of ovarian transposition during childhood or adolescence. Eighteen girls had ovarian transposition performed at a mean (+/- SEM) age of 9.4 +/- 1.2 years (range, 1.2 to 16 years). Twelve were prepubertal and six had menstruated at the time of ovarian transposition. The initial abnormalities were Hodgkin disease (5 cases), iliac Ewing sarcoma (3), medulloblastoma (2), ovarian seminoma (1), and vaginal or uterine tumor (7). The irradiation was external in 11 cases and local by vaginal curietherapy in 7 cases. Fifteen girls received chemotherapy. The ovarian transposition was bilateral in 15 patients and unilateral in 3 cases; in the latter the other ovary had been destroyed by the tumor or by abdominal irradiation. Ovaries were placed just below the iliac crest (15 cases) or posterolateral to the uterus (3); thus, the calculated ovarian radiation dose was up to 9.5 Gy. At the time of evaluation (8.6 +/- 0.9 years after ovarian transposition), 16 girls had menstruated and 2 remained amenorrheic because of major lesions of the vagina and uterus caused by the vaginal curietherapy. Basal plasma gonadotropin values were normal. Ovulation was documented in seven cases. Two pregnancies occurred. Complications of ovarian transposition were present in four patients: intestinal occlusion, dyspareunia, functional ovarian cysts, and pelvic adhesions with tubal obstruction. We conclude that ovarian transposition, performed before abdominopelvic irradiation during childhood, can preserve ovarian function. Longer follow-up is required to assess the risk of ovarian dystrophy because of vascular lesions or chemotherapy.