A 52-year-old man who had a history of trauma after a fall 8 years before reported pain in the right knee for 5 or 6 weeks. Roentgenographs and three-phase bone scintigraphy were performed 1 month earlier and myositis ossificans was suspected. Because the patient had continuous knee pain, a Tc-99m MIBI scan was performed to evaluate a possible tumor in the right knee. This scan showed increased accumulation in the knee area 15 minutes after intravenous injection (15 mCi). Pathologic examination of the lesion revealed myositis ossificans.