A 70-year-old man, who was diagnosed by computed tomographic scan as having bilateral synchronous adrenal myelolipomas 6 years ago during the follow-up of fatty liver, underwent tumor resection at our Department because of growth of bilateral tumors without any subjective symptoms. Histopathological examination revealed mature adipose tissue cells without atypism and areas of hematopoietic tissue, including the myelotic, lymphotic, erythrocytic, and megakaryocytic cells. The diagnosis of myelolipoma was confirmed. The in vivo doubling time of bilateral tumors was 16.1 months and 31.3 months, respectively.