Previous studies indicate that patients with eating disorders have alexithymic characteristics, as revealed by the Toronto Alexithymia Scale (TAS). The aim of the present study was to investigate the role of negative affect (anxiety and depression) in the relationship between eating disorders and alexithymia. In addition, we have evaluated whether the relationship between negative affect and alexithymia varies according to the type of eating disorder (anorexia and bulimia). Eighteen female patients and 16 female patients who met the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV) diagnostic criteria for restrictive anorexia nervosa and bulimia nervosa, respectively, and 18 healthy female controls matched by age and education were submitted to Beck Depression Inventory and Spielberger State-Trait Anxiety Inventory to assess depression and anxiety and the Toronto Alexithymia Scale (TAS-20) and the Bermond Vorst Alexithymia Questionnaire (BVAQ) to evaluate alexithymic characteristics. The findings indicated that, although anorexic and bulimic patients showed higher alexithymia scores compared to controls, this result could be mainly related to negative affect. In fact, taking negative affect into account, anorexic and bulimic patients did not show higher TAS-20 and BVAQ scores compared to controls. The only variable useful to discriminate among anorexics, bulimics and controls is the perceived inability to experience emotional feelings, which is higher in anorexic patients compared to the other two groups.