Pulmonary rehabilitation gradually has become the gold standard treatment for patients with severe lung disease, especially COPD. By definition, rehabilitation services are provided to patients with symptoms, most of whom have moderate-to-advanced lung disease. Because new therapeutic strategies, such as lung volume-reduction surgery and lung transplantation, require well-conditioned patients, pulmonary rehabilitation is becoming a crucial component of the overall treating strategy of many patients who heretofore were deemed untreatable. The positive results in several randomized trials have documented the effectiveness of pulmonary rehabilitation. Currently, pulmonary rehabilitation should be made available to all patients with symptomatic respiratory disease and be an integral part of any program considering high-risk surgery.