We experienced a case of primary gastric choriocarcinoma(PGC)treated by curative operation after neoadjuvant chemotherapy with S-1/CDDP. Gastric endoscopy was carried out on this 43-year-old woman with epigastric discomfort and revealed an ulcerative lesion in her stomach. Choriocarcinoma in the gastric lesion was pathologically shown by endoscopic biopsy, so we diagnosed the patient without another primary lesion as PGC. The patient was initially treated by five courses of neoadjuvant chemotherapy with S-1/CDDP due to the metastases of Virchow and intraabdominal lymph nodes, and then a curative operation could be performed because of disappearance of the lymph node metastases by neoadjuvant chemotherapy. The patient was continuously treated by S-1 after gastrectomy but was dead due to the multiple metastases of the liver and adrenals, and the multiple recurrences of lymph nodes four months after the surgery. Further therapeutic strategy by chemotherapies against PGC is needed to ameliorate the prognosis.