Survivors of the acute respiratory distress syndrome (ARDS) often report traumatic memories from the intensive care unit (ICU) and display a high incidence of post-traumatic stress disorder (PTSD). As it is known that subjects with PTSD often show sustained reductions in circulating cortisol concentrations, we examined the relationship between serum cortisol, traumatic memories and PTSD in patients after ARDS. We evaluated 33 long-term survivors of ARDS (7.5+/-2.9 years after discharge from the ICU) for pre-defined categories of traumatic memory from the ICU, hypothalamic-pituitary-adrenocortical axis reactivity to corticotropin and PTSD (by psychiatric interview). During evaluation, patients with multiple traumatic memories had significantly lower basal serum cortisol levels when compared to patients with no or only 1 category of traumatic memory, with no differences in peak cortisol levels after corticotropin stimulation between both subgroups. There was a significant negative correlation between basal cortisol levels and the number of traumatic memories present. PTSD symptom scores correlated with the number of traumatic memories but not with cortisol levels. These findings indicate that lower baseline cortisol levels in long-term survivors of ARDS are associated with an increased incidence of traumatic memories from the ICU, and that more traumatic memories are related to a higher incidence and intensity of PTSD symptoms.