Pulmonary rehabilitation is a relatively recent practice in pulmonary medicine which is classically described as a multidisciplinary program of care for patients with chronic respiratory impairment. There is solid evidence of effectiveness for the pulmonary rehabilitation and, with lower level of evidence, for some of its specific components. There is evidence of benefit for exercise tolerance, symptoms, Health-Related Quality of Life, and health care need with indirect evidence of positive effects on survival. One quarter to one third of patients do not have benefits from pulmonary rehabilitation, studies failing to identify any important predictors of treatment success or failure. Outcomes assessment in pulmonary rehabilitation is of main importance to evaluate its evidence-based effectiveness. Although, several questions remain unresolved, pulmonary rehabilitation programs should be included in the comprehensive treatment of patients with respiratory diseases.