The recent changes in diagnostic criteria for posttraumatic stress disorder (PTSD) in the 5th edition of the DSM and the 11th edition of the ICD marked a shift towards two perspectives on the same disorder. Previous studies indicate lower prevalence rates for the ICD-11-model as compared to the DSM-5 model. Main purpose of this study is to examine the concordance between ICD-11 and DSM-5 PTSD rates, and to assess the overlap of the two PTSD definitions with anxiety and depression among refugees.167 traumatized refugees were assessed with the PCL-5 for the DSM-5 PTSD model. A subset of the items was used as criteria for the ICD-11 model. Depression and anxiety were measured with the HSCL-25.The DSM-5-algorithm for PTSD identified significantly more cases (n = 147; 88%) than the ICD-11 algorithm (80%; n = 134). Level of agreement between the diagnostic systems was substantial (Κ = 0.67, p < .001) and 9% (n = 15) met criteria under one diagnostic system only. Overlap with depression and anxiety was high under both diagnostic systems.PTSD rates indicated a highly distressed sample of survivors of war and trauma. Our data provide further evidence that the DSM-5 diagnoses a larger number of persons than the ICD-11. Although the level of agreement was substantial, the observed discrepancies represent a challenge for research and practice to reliably identify individuals with PTSD. Especially for refugees, this might affect their access to mental health care and appropriate treatment during an asylum procedure.