This study examined the longitudinal course of posttraumatic stress disorder (PTSD) among two samples of Dutch aging military veterans: 576 veterans with a military disability pension and 198 community sample veterans, who fought in World War II, the former Dutch East Indies, and Korea. Both samples were investigated in 1992 and in 1998 with a standardized and validated instrument measuring PTSD symptoms. In 1992, 27% of the veterans with a military disability pension met the criteria for a PTSD diagnosis; in 1998, this was 29%. Of the community sample veterans, 9% reported a PTSD diagnosis in 1992, in 1998 this was 8%. The results provide strong support for the long-term persistence of PTSD symptoms. In addition, PTSD caseness at one time point was associated with significantly elevated PTSD symptom severity at the time of no PTSD diagnosis. No evidence was found for an aggravation of PTSD due to stressors associated with aging.