This systematic review examines the evidence on post-traumatic stress disorder (PTSD) following disasters, focusing on studies published from 1980 to February 2007. The review identified 284 reports of PTSD following disasters, categorized into human-made (n=90), technological (n=65), and natural disasters (n=116). Studies found that PTSD prevalence was highest among direct victims and first responders, with rates ranging from 20.3% to 44.3% in the first month after exposure. The general population had lower rates, typically between 5% and 10%. Longitudinal studies showed a general decline in PTSD prevalence over time, but some studies also reported increases. The review highlights methodological limitations and suggests future research should focus on longitudinal assessments and identifying high-risk populations to improve intervention strategies.This systematic review examines the evidence on post-traumatic stress disorder (PTSD) following disasters, focusing on studies published from 1980 to February 2007. The review identified 284 reports of PTSD following disasters, categorized into human-made (n=90), technological (n=65), and natural disasters (n=116). Studies found that PTSD prevalence was highest among direct victims and first responders, with rates ranging from 20.3% to 44.3% in the first month after exposure. The general population had lower rates, typically between 5% and 10%. Longitudinal studies showed a general decline in PTSD prevalence over time, but some studies also reported increases. The review highlights methodological limitations and suggests future research should focus on longitudinal assessments and identifying high-risk populations to improve intervention strategies.