The U.S. Air Force prisoners of war (POWs) experienced a profound degree of stress during the Viet Nam War. The psychiatric status of this population has been monitored by an ongoing voluntary follow-up program from the time of repatriation through the following five years. Data indicate a significant degree of psychiatric readjustment problems, which were greatest among POWs captured before 1969. These findings support the association of an unusually stressful environment with an increased incidence of psychiatric illness.