The aims of the study were to look at information on which the decision to ventilate chronic obstructive pulmonary disease (COPD) patients admitted to an intensive care unit (ITU) was based (including whether there was discussion with the patient, relatives and consultant), to identify indicators of poor prognosis, and to assess the outcomes of ventilation and functional capacity after discharge. A retrospective study of 27 months of admissions was carried out. The following variables were studied to see if they influenced prognosis: premorbid history, admission diagnosis, consultant involvement in the decision to transfer to ITU, admission chest radiograph, sputum bacteriology, arterial blood gases, APACHE II scores, duration of ventilation and complications in ITU. In-hospital mortality, post-discharge mortality and length of hospital stay were recorded. Functional capacity after discharge was assessed from the hospital clinic records and from general practitioners. Forty-six percent of case notes had inadequate premorbid information and no documented discussion occurred in 66% of patients/relatives. Poor prognostic indicators were admissions after cardiorespiratory arrest, cases discussed with consultants regarding ITU transfer, previous therapy with long-term oral steroids, and developing renal or cardiac failure in ITU. APACHE II scores were higher in the group that died. There was 49% hospital mortality and 59% 1-year mortality. Fifty-three percent of survivors were dependent upon carers and housebound, and general practitioners felt that 59% of survivors had a higher dependence on carers, a worse exercise tolerance and a poorer quality of life than before admission. The decision to ventilate is often made with inadequate background history, which could be sought from general practitioners, hospital case notes and family. There is significant morbidity and mortality following ventilation. Further prospective studies are required to help select which COPD patients should be ventilated.