The case of a female patient who failed to get pregnant due to delayed menstruation is reported. Gynecological examination showed that the patient had a male pubic distribution, hypertrophic clitoris, unobstructed vagina and hypertrophic cervices with smooth and medium texture. B ultrasonic examination detected a 42 x 30 mm in size medium echo mass. This mass had irregular shape, smooth surface, relatively clear boundary and hard texture. Examination with paraffin-embedded section indicated that the tumor was composed of supporting cells and to a lesser amount of interstitial components. Some regions had particle-like cell differentiation. These results suggested that the tumor was gynandroblastoma. We found that the increased level of serum testosterone in the patient was the reason for amenorrhea and infertility. The diagnosis and treatment for patients with gynandroblastoma is also discussed.