The prevalence of obesity is increasing. The mortality and morbidity among obese intensive care unit (ICU) patients has been a matter of concern. Most of the retrospective studies performed have yielded contradictory results. Recently, two large prospective studies showed that respiratory failure, length of mechanical ventilation and ICU acquired infections were increased in obese patients. Obesity was, however, not associated with increased mortality. The results were confirmed by a meta-analysis which showed that obesity was associated with increased morbidity but not with increased mortality.