A rare case of CA19-9 producing tumor in undescended testis was presented. A forty-three year old man visited to our hospital with a chief complaint of left flank pain. Serum tumor markers (AFP, beta-HCG, and CA19-9) were elevated. Abdominal CT scan demonstrated large solid mass with multilocular cysts were capsulated. The tumor resection was performed after 3 courses of CEB (Carboplatin, Etoposide, and Bieomycin) chemotherapy. Macroscopically, the tumor was consisted of necrotic mass and multilocular cysts. The tumor size was 25 x 8 x 5 cm and weight was 1000 g. Microscopically, the large part of tumor was necrotic due to chemotherapy, and the teratoma component which was consist of neural, muscular, and digestive tissue was seen in some area. In conclusion, this is a rare case of mixed germ-cell tumor in undescended testis located in abdomen.