The recently published eleventh edition of the International Classification of Diseases (ICD-11) included the new condition, complex posttraumatic stress disorder (CPTSD), in addition to posttraumatic stress disorder (PTSD). Diagnosis of the CPTSD implies the existence of PTSD symptoms as well as three additional clusters of symptoms, commonly referred to as Disturbances in self-organization (DSO). These three additional clusters of symptoms reflect more pervasive psychological disturbances, which occurre after a traumatic experience. The main goal of this study was to examine the frequency of CPTSD in a clinical sample of Homeland War veterans according to the new ICD-11 criteria, and the additional goals were to compare two groups of respondents (PTSD and CPTSD) according to sociodemographic features, somatic and psychiatric comorbidity, exposure to war trauma , type of treatments, use of medication and level of functioning. A survey was conducted on 160 respondents, who are veterans of the Homeland War, and are under ambulatory treatmant at Psychiatric Clinic in Clinical Hospital Center of Rijeka, under the diagnosis of PTSD. The results show that 129 of respondents (80%) meet the criteria for complex PTSD, while 31 of them (20%) meet the criteria only for PTSD. Also, the results show that CPTSD patients estimate that symptoms of disease significantly affect their level of functionality. This research will contribute to existing scientific knowledge and a better understanding of the CPTSD, which is particularly important in the context of the population of Croatian Homeland War veterans, who have been exposed to prolonged and multiple traumatic experiences during the war, as the new classification will have implications in clinical work with that population.