OBJECTIVE Eating disorders (ED) are associated with a higher prevalence of post-traumatic stress disorder (PTSD). However, the impact they may have on the clinical features and severity of the ED remains unknown. In this study, we assessed the prevalence and the impact of PTSD in a disordered eating population sample. METHODS We recruited patients with eating disorders during a period of 6 months, in 2014. The patients underwent a semistructured diagnostic interview by trained psychiatrists. The severity of eating behaviours and PTSD was assessed using the Eating Disorder Inventory 2 and the Impact of Event Scale - Revised. RESULTS One hundred and thirty patients (57 patients with anorexia nervosa, 26 with bulimia nervosa, 18 with eating disorder not otherwise specified and 29 with binge eating disorder) were included. Our analyses revealed a PTSD rate of 33.9% in patients with ED. No difference was observed between the ED subtypes. Severity of ED was significantly higher among patients suffering from PTSD. Specific clinical characteristics of the ED-PTSD association have been found. Analyses revealed a significantly higher level of insecurity, interpersonal distrust, impulsivity and a decrease of interoceptive awareness. CONCLUSIONS The frequency and negative impact of PTSD on ED reinforce the need for a systematic clinical evaluation and the implementation of specific care.