Thoracic injuries remain a leading cause of death in trauma victims, and many patients with chest injuries die at the scene of injury. Problems related to cardiac or great vessel injuries, which are outside the scope of this article, are certainly among the “complex” thoracic injuries. We have focused our attention on four specific problems that we have found to be difficult to manage, either from a judgment or a treatment standpoint. These complex problems are (1) the diagnosis and management of air leakage not associated with pneumothorax, (2) the management of major thoracic esophageal injuries, (3) problems related to penetrating trauma, particularly those pulmonary resections for trauma, and (4) the diagnosis and management of retained hemothorax and empyema, especially in the patient with blunt trauma.