The effects of a pulmonary rehabilitation program on 44 patients with chronic obstructive pulmonary disease (COPD) were compared to a control group. The treated group was admitted to the program for a period of three months. The program consisted of several parts, such as physical training, health education, and psychological and social matters. Before participation, the patients were thoroughly examined and provided with optimal medical treatment. Both groups were assessed by means of biometrical tests and questionnaires for a period of 2 years. The rehabilitation group improved significantly in endurance, psychological parameters, and consumption of medical care. Working days increased and their way of life became more active. Smoking habits and body fat percentage decreased. Bronchial hyperreactivity, need for pulmonary drugs, and coughing and sputum production did not improve in the rehabilitation group compared to the control group. Airway obstruction, expressed as forced expiratory volume in one second, and complaints of dyspnea, allergy and hyperreactivity scores on questionnaires improved only in the short term (< 1 year), but did not improve significantly in the long term. This study shows that pulmonary rehabilitation can result in improvements in patients with asthma or COPD who have many complaints despite the fact that their pulmonary function is not severely disturbed.