Sclerosing stromal tumor of the ovary is a rare benign neoplasm, with distinctive clinical and pathologic features. It occurs predominantly in females during the second and third decades of life. Histologically, it is composed of cellular and acellular collagenized areas, and edematous stromal areas, and at ultrasonography and computed tomography is seen as a distinctive mixed solid and cystic mass lesion. We report a case of sclerosing stromal tumor of the ovary in a 15-year-old girl with a history of menorrhagia since menarche. Ultrasonography revealed the tumor as a well-defined, lobulated, heterogenous echogenic pelvic mass, while at CT, a huge pelvic mass 9x9x10 cm in size, was seen. This comprised a well-enhanced internal solid portion, a capsule, septa, and a non-enhanced cystic portion.