Intraosseous hemangiomas are rare, benign bone tumors usually affecting the bones of the axial skeleton. Its incidence in the long bones is extremely rare. We report a 19-year-old boy with solitary intraosseous hemangioma of the proximal ulna. Radiographs and computed tomography images showed a well-defined osteolytic lesion involving the right proximal ulna. Magnetic resonance imaging showed intermediate signal intensity on T1-weighted images and increased signal intensity on T2-weighted images with internal trabeculae and peripheral post-contrast enhancement. Postcurettage histologic diagnosis of intraosseous hemangioma was made.