This study aimed to assess whether patterns and outcomes of acute respiratory distress syndrome (ARDS) have changed due to improvements in mechanical ventilation techniques and support of critically ill patients, by comparing patients from two different periods in the same hospital. We reviewed data from all patients with a diagnosis of ARDS (according to American-European Consensus Conference criteria) who were treated in our multidisciplinary department of intensive care (Erasme Hospital, Brussels) between January 2006 and April 2009 (group B, n=210) and compared them with our previously reported data (January 1993 to February 1995) (group A, n=129). The prevalence of ARDS has decreased (from 2.5% in group A to 1.7% in group B, p<0.001). ARDS patients are now older and sepsis-related ARDS is more common. Multiple transfusion and trauma are less common causes of ARDS than in the past. Intensive care unit length of stay among survivors is shorter (13 ± 9 versus 17 ± 17 days, p=0.025), and there was a trend to lower mortality rates in the more recent cohort (46% versus 52%, p=0.158). Multiple organ failure (MOF) was the most common cause of death in both periods. The pattern of ARDS has changed over time in our department. Patients with ARDS are now older and more severely ill. Sepsis-related ARDS is more frequent whereas trauma-related and/or transfusion-related ARDS has decreased. MOF still represents the most frequent cause of death.