Thoracoscopy was used in the diagnosis and treatment of three patients with diaphragmatic disorders, including traumatic injury of the diaphragm, partial eventration of the diaphragm, and catamenial pneumothorax (endometriosis of the diaphragm). An excellent view of the diaphragm was obtained by using thoracoscopy. The diaphragmatic injury was repaired primarily, the eventration plicated, and the focal endometriosis resected. Recovery was rapid and uneventful in all three patients. Thoracoscopic surgery, although relatively new, may be an acceptable alternative to the conventional operative management of diaphragmatic disorders and may actually reduce the morbidity and mortality associated with thoracotomy.