Disasters are traumatic events that may result in a wide range of mental and physical health consequences. Post-traumatic stress disorder (PTSD) is probably the most commonly studied post-disaster psychiatric disorder. This review aimed to systematically assess the evidence about PTSD following exposure to disasters. MethodA systematic search was performed. Eligible studies for this review included reports based on the DSM criteria of PTSD symptoms. The time-frame for inclusion of reports in this review is from 1980 (when PTSD was first introduced in DSM-III) and February 2007 when the literature search for this examination was terminated.