A 41-year-old male patient was admitted to Maebashi Red Cross Hospital with a complaint of a left flank mass. Left renal tumor and contralateral adrenal mass were revealed by ultrasonography, computed tomography and magnetic resonance imaging. Endocrinological examinations were unremarkable. Left nephrectomy and right adrenalectomy were performed simultaneously. Histological findings of the left renal tumor confirmed clear cell carcinoma, and those of the right adrenal tumor revealed myelolipoma with mature adipose tissue and hematopoietic elements.