BackgroundThe Russian invasion of Ukraine has driven millions of Ukrainians away from their homes. Among these, the majority have likely experienced war-related potentially traumatic events, and some will experience symptoms of posttraumatic stress disorder (PTSD). The aims of the study are to estimate the prevalence of PTSD and Complex PTSD (CPTSD) in displaced Ukrainians and examine associations between war- and other potentially traumatic exposures and (C)PTSD. MethodsQuestionnaires were distributed to all registered adult Ukrainians (18+) who arrived in Denmark between February 24th 2022 and February 15th 2023 (N = 18,389). We estimate the prevalence of war exposures, other potentially traumatic exposures, and (C)PTSD. In logistic regression analyses, we test if exposure to war and other potentially traumatic events are associated with PTSD and CPTSD. ResultsThe final sample size was 6993 (38.0 %). Responders were more likely to be female and younger than non-responders. Prevalence of PTSD and CPTSD was 15.9 % and 13.5 %, respectively. Female gender, high education, and loss of a relative due to the war were associated with (C)PTSD. Direct and indirect exposure to war and combat was related to PTSD but not CPTSD, while exposure to war prior to the 2022 invasion was related to CPTSD but not PTSD. LimitationsThe study is cross-sectional and based on self-report. ConclusionClose to one third of the sample fulfill the criteria of PTSD or CPTSD. War exposures are differentially related to PTSD and CPTSD. The findings illustrate that trauma-related psychopathology is a pertinent problem in displaced Ukrainians.