There has been a growing interest in treating malignant germ cell tumors of the ovary with adjuvant chemotherapy following appropriate surgery. This is a report of 3 patients treated in this manner. Of interest is the finding in all 3 patients of residual mature metastatic teratomatous tissue representing many tissue types. The concept of possible chemotherapeutic "retroconversion" or "in situ destruction" of immature tissue may be the mechanism for this result. All patients are alive and presumably well at the time of this report.