Growing teratoma syndrome (GTS) is defined as metastatic masses during or after chemotherapy for germ cell tumors, which contain only mature teratoma components. The peritoneum of the pelvis and abdomen and the retroperitoneum are the most frequent sites of metastasis. We report a case of GTS of the ovary showing three patterns of metastasis: dissemination, lymphogenous metastasis, and hematogenous metastasis. The patient initially presented 5 years ago with a mixed germ cell tumor of the left ovary and positive cytology of ascites. After surgery and chemotherapy, mature teratomas recurred as pelvic peritoneal dissemination, a para-aortic lymph node mass, and a lung mass. Our case highlights the importance of long-term follow-up and a whole-body search. We think that our case is suggestive regarding the mechanism of critical GTS.