We report a case of infantile myofibromatosis in a male infant with involvement of the lungs and subcutaneous tissue. We studied our case by light microscopy, immunohistochemistry and electron microscopy. The results reveal that this entity is of a myofibroblastic nature. We reviewed 165 cases including our case. We believe this is the first report in Korea of infantile myofibromatosis with pulmonary involvement.