Background: The current study sought to advance the existing literature by providing the first assessment of the factorial and discriminant validity of the ICD-11 proposals for posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD) in a nationwide level. Methods:A nationally representative sample from Israel (n=1,003) using a disorder-specific measure (ITQ; International Trauma Questionnaire) in order to assess PTSD and CPTSD along with the Life Events Checklist and the World Health Organization Well-Being Index. Results: Estimated prevalence rates of PTSD and CPTSD were 9.0 and 2.6%, respectively. The structural analyses indicated that PTSD and disturbances in self-organization symptom clusters were multidimensional, but not necessarily hierarchical, in nature and there were distinct classes that were consistent with PTSD and CPTSD. Conclusions: These results partially support the factorial validity and strongly support the discriminant validity of the ICD-11 proposals for PTSD and CPTSD in a nationally representative sample using a disorder-specific measure; findings also supported the international applicability of these diagnoses. Further research is required to determine the prevalence rates of PTSD and CPTSD in national representative samples across different countries and explore the predictive utility of different types of traumatic life events on PTSD and CPTSD.