Adrenal myelolipoma is a rare, benign and biochemically inactive tumor. It is usually diagnosed incidentally by radiological methods and is known to be associated with obesity, hypertension, endocrinological disorders and some malignancies. We report herein the association of a myelolipoma with a gastrointestinal stromal tumor. To our knowledge this is the first report of such an association to date. A 67-year-old male patient admitted to our clinic with abdomimal pain and fever; he had a history of hypertension and diabetes mellitus. In physical examination, a mass involving the right quadrants was palpated. Computerized tomography revealed a right retroperitoneal mass, probably originating from the kidney or cecum. In laparotomy, the tumor (12 cm radius and 1500 g) localized on the superior of right kidney was excised. Abdomen exploration revealed another mass with 10 cm radius 100 cm distal to the ligamentum of Treitz and segmental jejunal resection and anastomosis were applied. The pathological diagnosis was reported as myelolipoma for the retroperitoneal mass and leiomyosarcoma for the jejunal mass. Myelolipoma is a benign tumor, involving mature fat and hematopoietic stem cells. Pathogenesis is still not clear and the microscopical characteristics are hematopoietic, lipoid, and reticuloid cells and megakaryocytes. Myelolipomas are reported to be associated with some other malignancies (especially renal), but this is the first report showing the association with a leiomyosarcoma. Therefore, leiomyosarcoma should also be one of the possible associations kept in mind by the physician in the diagnosis and treatment of myelolipomas.