Patients with a long stay in the intensive care unit because of chronic critical illness consume many resources, and yet their outcome may be poor. We evaluated the long-term outcome of patients spending more than 60 days in the intensive care unit. We performed a retrospective cohort and prospective follow-up study of 78 patients staying more than 60 days in the 19-26 bed mixed intensive care unit of a university hospital from November 1995 to January 2003. The mortality in the intensive care unit was 38%; at 1 and 5 years it was 56% and 67%, respectively. Advanced age, prior pulmonary disease, long duration of renal replacement therapy, a low oxygenation ratio and platelet count and high Simplified Acute Physiology Score II and Sequential Organ Failure Assessment scores on day 60 influenced long-term mortality. A Simplified Acute Physiology Score II of 50 or a Sequential Organ Failure Assessment score of 8 or higher was associated with 100% mortality during follow-up. The overall 5-year survival rate of 33% suggests that prolonged intensive care may be worth the effort in certain patients. © 2005 Blackwell Publishing Ltd.