A case of adrenal myelolipoma is reported in a 14-year-old girl. Abdominal ultrasound examination revealed a left-sided ovarian cyst 13 cm in diameter and an 8 x 8-cm hyperechoic heterogenous solid mass localized in the right adrenal gland. The ovarian cyst and adrenal mass were removed surgically. Histological examination of the adrenal mass revealed a proliferation of mature adipose tissue with bone marrow-like hematopoietic elements. The ovarian cyst was a simple serous cyst.