This paper reviews the literature on performance on standard neuropsychological tests among individuals with posttraumatic stress disorder (PTSD). Of 19 studies, 16 reported impairment of attention or immediate memory (or both); however, most of these studies included PTSD patients with significant psychiatric comorbidity, so that the extent to which the observed deficits are specifically attributable to PTSD remains unclear. Other potential confounds, including medical illness, substance abuse, and motivational factors, further preclude definitive conclusions at present. Results of structural and functional neuroimaging studies of PTSD are also summarized. Two studies have reported correlations between hippocampal volume and cognitive findings in PTSD patients; functional studies have indicated specific findings in limbic regions, although the relationship of these results to neuropsychological performance remains to be explored.