BACKGROUND A rare malignant germ cell tumor of the ovary during pregnancy was detected by screening of maternal serum alpha-fetoprotein (MSAFP). Treatment of this uncommon tumor during pregnancy incorporated combination chemotherapy including etoposide. CASE An 18-year-old primiparous woman undergoing antenatal genetic screening was found to have an extremely elevated MSAFP of 477.8 IU/mL, or 12.46 multiples of the median. Oophorectomy and staging laparotomy at 20.5 weeks' gestation resulted in the diagnosis of mixed germ cell tumor of the ovary, with both endodermal sinus tumor and grade 3 immature teratoma. The patient received three courses of cis-platinum, etoposide, and bleomycin. Maternal serum AFP titers had returned to normal pregnancy levels by the start of the second course. A healthy female infant was delivered at 39 weeks' gestation following induction of labor for pregnancy-induced hypertension. CONCLUSION Elevated MSAFP levels may be a presenting sign of malignant ovarian germ cell neoplasms. This report describes both surgical and chemotherapeutic treatment of a germ cell malignancy during pregnancy, with delivery at term. To date, major fetal toxicity from chemotherapy has not been identified.