IntroductionDue to the war in Tigray, 2.1 million people (31% of the total population) were internally displaced. Epidemiological evidence shows that the burden of mental health is higher in war/conflict and post-conflict areas of the world compared to non-conflict places, especially for those who have experienced targeted ethnic violence as a result of civil and political unrest. Post-traumatic stress disorder is one of the common psychiatric disorders experienced during war. Thus, this study aimed to assess the level and aggravating factors of PTSD during the war in Tigray.MethodsA community-based cross-sectional study was conducted among 2132 IDP family heads in Tigray from August 6–30, 2021. Study participants were recruited using a multi-stage sampling technique. Data were collected using a pretested structured questionnaire through face-to-face interviews. The PCL-C checklist, derived from DSM-IV criteria, was used to assess the magnitude of post-traumatic stress disorder. The entered data were exported to the SPSS version 26 statistical package for analysis. Summary statistics were computed, and logistic regression analysis was used to investigate factors associated with developing PTSD.ResultsA total of 2071 IDPs were surveyed with a response rate of 99.7%. The survey revealed that the level of PTSD among community-hosted IDPs was 57.7%; 95% CI 55.5%-59.8%. Older age (> 50) (AOR 3.1, 95% CI 1.497–6.421), primary and secondary school attendance (AOR 2.1, 95% CI 1.344–3.279; and 1.697, 95% CI 1.067–2.7) respectively, internally displaced persons with a family size of > 6 members (AOR 1.821, 95% CI 1.124–2.95), disability due to the war (AOR 1.702, 95% CI 1.077–2.69), and loss of contact with family members (AOR 1.472, 95% CI 1.032–2.099) were significantly associated with PTSD.ConclusionThe overall level of PTSD among cIDPs was found to be high (57.7%). Almost every other IDP developed this serious mental health syndrome. Immediate psycho-social health intervention is needed by local and international organizations in collaboration with governmental and non-governmental institutions based on the study's findings.