We report a case of intraosseous lipoma involving the ilium in a 37-year-old male. There were no clinical symptoms. Plain films suggested the diagnosis, which was confirmed by computed tomography and magnetic resonance imaging with fat-cancelling sequences. However, we were unable to rule out fatty involution of an old aneurysmal bone cyst. Modern imaging techniques are very reliable for the diagnosis of intraosseous lipoma. Computed tomography is usually sufficient to establish the diagnosis and to guide therapeutic decisions.