Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor usually seen within the first and second decade. They are extremely rare in adults, constituting less than 1% of adult lung tumors. It's usually benign, but it had a tendency for local recurrence. We report a case of asymptomatic inflammatory myofibroblastic tumor of lung in a 46-year-old non-smoker woman.