Alexithymia, which is the inability to recognise and describe one's own emotions, is a transdiagnostic feature across eating disorders (EDs) and it has been associated with prolonged stress exposure. Therefore, we evaluated whether alexithymia was associated with hypothalamus-pituitary-adrenal (HPA) axis functioning, the main endogenous stress response system, in patients with anorexia nervosa (AN) or bulimia nervosa (BN).