The oxygen cost of eccentric exercise is lower than that of concentric exercise at similar work-loads. In this study, the response to eccentric cycle exercise training (EET) in addition to general exercise training (GET) on exercise performance and quality of life was investigated in 24 patients with severe chronic obstructive pulmonary disease (COPD). All patients had a normal resting PaO2 and an arterial oxygen saturation (SaO2) below 90% at Wmax, achieved during a maximal incremental concentric cycle exercise test. The patients participated in a comprehensive inpatient pulmonary rehabilitation programme of 10 weeks. They were randomly assigned either to GET (GET group: mean FEV 38% predicted) or to GET and additional EET (GET/EET group: FEV1 45% predicted). During EET, the patients were able to cycle eccentrically for 15 min continuously at a mean of 160 (69%) of Wmax whereas the Borg dyspnoea score did not exceed 3.0 and SaO2 did not fall below 90%. Parameters of cardiocirculatory fitness and gas exchange improved in the GET/EET group but no further improvement in exercise capacity occurred compared to GET. It is concluded that eccentric cycle exercise is a safe and attractive training modality for patients with severe COPD and can be performed at a high intensity without the patient becoming out of breath or needing supplemental oxygen.