A 15-year-old, legally male patient came to our department with chief complaint of gynecomastia. Serum testosterone was at a low level of 1.6 ng/ml, and prolactin a high level of 23 ng/ml. Blood type was a mixed type of both type A and type B, and a chromosomal analysis with peripheral blood lymphocytes demonstrated a mosaic of 46, XX/46, XY. During the follow-up, he complained a painful swelling in his right scrotum, and received an emergent surgery. A large amount of blood was noted in the right scrotum. Unicorn uterus, Fallopian tube and finbriae were observed, and a thumb-sized gonad with hemorrhage and fissure was also seen in the upper part of the scrotum. The right gonad was an ovary and no testicular tissue was confirmed in the right scrotum, whereas the right vas deferens was noted. The left testis was accompanied by an induration on its upper pole which was histologically found to be ovarian tissue. The patient was diagnosed as a true hermaphroditism with 46, XX/46, XY chimera that had an ovary with inguinal uterus hernia and an unusual vas deferens in the right scrotum and an ovotestis in the left. It was considered that an adequate amount of testosterone secreted from the left testis during the early embryonal period might have affected the descent of the right ovary into the scrotum and on the development of the right vas deferens.