: The introduction of the diagnosis of complex posttraumatic stress disorder (CPTSD) by ICD-11 is a turning point in the field of traumatic stress studies. It's therefore important to examine the validity of CPTSD in refugee groups exposed to complex trauma (CT) defined as a repeated, prolonged, interpersonal traumatic event. : The objective of this study was to compare DSM-5 and ICD-11 post-traumatic stress disorder diagnoses and to evaluate the discriminant validity of ICD-11 PTSD and CPTSD constructs in a sample of treatment-seeking refugees living in Italy. : The study sample included 120 treatment-seeking African refugees living in Italy. All participants were survivors of at least one CT. PTSD and CPTSD diagnoses were assessed according to both DSM-5 and ICD-11 criteria. : Findings revealed that 79% of the participants met the DSM-5 criteria for PTSD, 38% for ICD-11 PTSD and 30% for ICD-11 CPTSD. Generally, ICD-11 CPTSD items evidenced strong sensitivity and negative predictive power, low specificity and positive predictive power. Latent class analysis results identified two distinct groups: (1) a PTSD class, (2) a CPTSD class. None of the demographic and trauma-related variables analysed was significantly associated with diagnostic group. On the other hand, the months spent in Italy were significantly associated with PCL-5 score. : Findings extend the current evidence base to support the discriminant validity of PTSD and CPTSD amongst refugees exposed to torture and other gross violations of human rights. The results suggest also that, in the post-traumatic phase, the time spent in a 'safe place' condition contributes to improve the severity of post-traumatic symptomatology, but neither this variable nor other socio-demographic factors seem to contribute to the emergence of complex PTSD. Further investigations are needed to clarify which specific vulnerability factors influence the development of PTSD or CPTSD in refugees exposed to complex trauma.