We previously reported that older veterans with post-traumatic stress disorder (PTSD) are nearly twice as likely to develop dementia compared to veterans without PTSD. Recently we found that younger veterans (mean age: 42) with PTSD and cognitive impairment (CI), defined as > 1.5 SD below the mean on a cognitive domain (i.e., memory, executive function, language or visospatial abilities), have smaller hippocampal and frontal white matter volumes than PTSD+ veterans without CI. Because hippocampal atrophy and memory impairment are both risk factors for Alzheimer’s disease (AD), this may be a potential link between the two disorders. The goal of this proposed research project is to further investigate the potential links between PTSD and dementia by pursuing the following aims: (1) Replicate and expand our preliminary finding of reduced hippocampal and frontal white matter volume in PTSD+ subjects with CI by performing secondary analyses of the magnetic resonance imaging (MRI) and neuropsychological data from the Sierra Pacific (VISN 21) Mental Illness Research Education and Clinical Centers (MIRECC) PTSD project. (2) Assess the current cognitive status of PTSD+ subjects from the MIRECC PTSD and our Department of Defense funded Gulf War Study with the modified version of the Telephone Interview for Cognitive Status. (3) Compare the neuropsychological profiles of subjects with PTSD+ and CI with that of subjects with mild cognitive impairment (MCI), a transition state between normal aging and Alzheimer’s disease (AD). Given the growing number of veterans and civilians living with PTSD and the expected increase in the incidence of dementia, there is an urgent need to understand the relationship between PTSD and dementia. This research will provide a new direction for efforts to improve the health of those with PTSD and to prevent further morbidity and mortality in this population.