Krukenberg tumor with pregnancy is rare but it is a challenge for treatment and diagnosis. The authors report a case of a 29-week pregnant patient with a massive bilateral Krukenberg tumor which was misdiagnosed as myoma preoperatively and as ovarian stromal tumor intraoperatively. Prenatally the woman was asymptomatic except for preeclamptic symptoms, but red acne on the skin and elevated testosterone were observed. Pelvic ultrasound detected a heterogeneous solid mass mimicking a subserous myoma. The deterioration of preeclampsia prompted a cesarean section, but the neonate died nine days after he was born.A bilateral adnexal mass was found and considered as stromal tumor by frozen section because of luteinization of the stroma. The final pathology showed low differentiation adenocarcinoma of ovary, which was confirmed by gastric biopsies. The patient had undergone chemotherapy 16 times without surgical debulking and she was in generally well 1.5-year follow-up.