Primary sarcoma of the lung is a rare malignancy. We now report the first case of a pediatric patient with a pulmonary primary sarcoma and left atrial involvement treated by combined resection. The patient was an 11-year-old boy admitted for right hemiplegia who was found to have a mass localized to the right superior lobe of the lung with thrombosis in the right superior pulmonary vein extending into the left atrium. Combined resection was performed under extracorporeal circulation and further treatment included chemotherapy and autologous bone marrow transplantation. Pathology of the tumor revealed a high-grade undifferentiated sarcoma and the definitive staging was T4 N0 M0. The patient did well postoperatively but developed extsathoracic metastases and died 24 months later of progressive disease. Combined resection of tumor in the lung and left atria can be safely performed in a pediatric patient with pulmonary sarcoma. However, new chemotherapy protocols may be necessary to extend the survival of patients with this rare agressive disease.