Pulmonary carcinosarcoma is a rare disease entity defined as a neoplasm, which has biphasic features consisting of both epithelial and sarcomatous components. It has been reported that the most frequent epithelial component is squamous cell carcinoma, while the most frequent sarcomatous component is rhabdomyosarcoma. Pulmonary carcinosarcomas with osteosarcoma components are even rarer. We report a case of a potentially curative resection for carcinosarcoma with an osteosarcoma component. Thoracic surgeons should be aware of this rare tumor when lung tumors with ossification are encountered.