To investigate the longitudinal course of mean 24-hour urinary cortisol excretion in posttraumatic stress disorder (PTSD), the authors evaluated 24-hour cortisol excretion in 28 Holocaust survivors 10 years after obtaining an initial estimate. Cortisol levels increased in participants whose PTSD had remitted (n = 3) but declined in participants who developed PTSD (n = 3) or whose PTSD status did not change over time (PTSD+: n = 14, PTSD-: n = 8). Cortisol levels at Time 1 predicted diagnostic status change better than psychological variables, including exposure to traumatic events between assessments. The authors conclude that cortisol levels are affected by change in PTSD status and age.