Eighteen patients aged 4 to 18 years (median, 10 years) were treated at the Children's Cancer Research Center of The Children's Hospital of Philadelphia (CHP) from September 1973 to September 1983 for malignant ovarian tumors. The pathologic categories were endodermal sinus tumor (eight patients), embryonal carcinoma (three patients), pure dysgerminoma (three patients), adenocarcinoma (three patients), and malignant granulosa-cell tumor (one patient). In 1973 and 1975, respectively, two patients with endodermal sinus tumors were treated with surgical removal with or without radiation therapy (RT) and chemotherapy with vincristine (Vc) and actinomycin D+ cyclophosphamide + Adriamycin (Adria Laboratories, Columbus, OH) (ACAdr); both developed local recurrence within 12 months and died of tumor. Since 1977, four of six patients with endodermal sinus tumors have been managed successfully with surgery followed by chemotherapy with cisplatin (P), bleomycin (B), vinblastine (Vb), and ACAdr; none received RT. One died of recurrent tumor and the other died of congestive heart failure attributed to Adriamycin (Adr). All three patients with embryonal carcinoma were well after surgical excision alone (one patient) or surgery and chemotherapy with cisplatin + bleomycin + vinblastine (PBVb) + ACAdr (two patients). Treatment of the remaining seven patients included excision alone (two patients) or excision and chemotherapy (five patients) with various combinations of Vc, ACAdr, and P. One patient with granulosa-theca cell tumor also received whole abdominal RT (3000 rad by external beam), and died of congestive heart failure attributed to Adr. The other six children were free of detectable tumor 16 months to 8 years from diagnosis. Chemotherapy with PBVb and actinomycin D + cyclophosphamide (AC) should be used in the postoperative management of young persons with malignant ovarian tumors. Adr is of doubtful value and may be considerably toxic. RT is of limited use and usually is not indicated.