ABSTRACT Background: Research on the prevalence of ICD-11-based complex posttraumatic stress disorder (CPTSD) in nationally representative samples is lacking, with no such studies conducted considering national Polish samples until now. Objectives: The primary aim of this study was to explore profiles of study participants in terms of either PTSD or CPTSD symptoms regarding to ICD-11 diagnosis with the aid of latent profile analysis. We also investigated the relationship between the types and cumulative number of adverse childhood experiences (ACEs) with the probability of CPTSD rate in a national sample of Poles. Methods: A representative sample of Polish adults (n = 3,557) participated in this study. ACEs were assessed using the Adverse Childhood Experiences Questionnaire, while the core features of PTSD and CPTSD were measured using the International Trauma Questionnaire. Results: The findings showed a 11% prevalence rate of probable CPTSD in the studied sample of Poles. Sexual abuse, emotional neglect, physical neglect and having the experience of a mentally ill household member were the most significant predictors of potential diagnosis. Furthermore, significant differences concerning lifestyle data were observed in the group of participants with CPTSD. Conclusions: The current rate of probable CPTSD in Poland is substantially higher than the respective data reported for other countries. We also noted that the ICD-11 diagnosis of CPTSD may not apply to all cultural environments. Finally, it was observed that the ACEs – CPTSD association may depend both on the ACEs types as well as on their overall cumulative character.