The negative behavioural and emotional symptoms of Post-Traumatic Stress Disorder (PTSD) have been extensively reported in the literature. However, much less is known about the neuropsychological and neurobiological characteristics of the disorder. This thesis consists of two papers, the first being a review which highlights the emerging picture of literature in the field of neuropsychology in PTSD, with particular reference to findings in those cognitive domains of general intellectual functioning, memory, attention and executive function. Given that the findings associated within these domains are mixed, the second paper reports the outcome from a neuropsychological study of cognitive differences that was conducted to contribute to current knowledge in the area of neurocognition and visual memory in PTSD in particular. Trauma exposure, current PTSD, depressive and anxiety symptoms and performance on a range of neuropsychological tests were examined in tertiary care outpatients with PTSD (n=26), individuals who had been exposed to severe trauma but without current PTSD (n=26), and healthy controls (n=26). In addition to previously reported deficits in verbal learning and fluency in PTSD, deficits in visual spatial memory were also found. These observable deficits in visual memory may reflect characteristic features of PTSD, such as reported difficulties in remembering certain aspects of traumatic events and the presence of visual flashbacks. It is uncertain whether these deficits represent a risk factor for PTSD, or a consequence of trauma, as suggested by research in animal models.