OBJECTIVE Complex posttraumatic stress disorder (CPTSD) is a newly proposed diagnosis in the International Classification of Diseases-version 11, which is currently intensively investigated. Childhood trauma is regarded as main source of CPTSD symptoms, even in later life. Induction of DNA methylation changes by childhood trauma may contribute to its long-lasting adverse health consequences. The current study analyzed the correlation of genome-wide DNA methylation profiles with complex posttraumatic sequelae in buccal epithelial cells from 31 elderly former indentured child laborers (Verdingkinder) using the Infinium Illumina 450k Human DNA methylation chip. RESULTS DNA methylation modifications indicated experiment-wide significant associations with the following complex posttraumatic symptom domains: dissociation, tension reduction behavior and dysfunctional sexual behavior. Differentially methylated CpG sites were mapped to the genes huntington associated protein 1 (HAP1), RAN binding protein 2 (RANBP2) and proteasome subunit alpha 4 (PSMA4), respectively. In addition, the methylation of cg07225277 located in carnosine synthase 1 (CARNS1) correlated with trauma symptom complexity. Our pilot data suggest correlation of DNA methylation modifications with complex posttraumatic symptoms in elderly individuals subjected to prolonged and complex childhood trauma. More comprehensive and elaborated studies should be carried out to analyze epigenetic modifications associated with CPTSD.