Alexythimia is a psychological construct characterized by difficulty describing emotions and distinguishing them from somatic components of the emotional activation. Patients with eating disorders (ED) or substance use disorders (SAD) commonly present also impairment of recognition of facial expressions and deficits in social inference. Patients with ED and SAD may present impulsiveness, difficulty in emotion-focused coping skills, and search for a concrete relief from psychological suffering. The purpose of study is to compare the ED, SAD and healthy controls (HC), in several variables, including Alexythimia, empathy, and ability to recognize emotions, social inference. Thirty-two patients with ED, 27 patients with SAD and 31 HC were recruited between September 2016 and April 2016 at the psychiatric ward of Novara Hospital, nursing home of Nebbiuno and the nursing home of Viverone. We administrated to patients the same battery of tests, composed by Toronto Alexithymia Scale-20 (TAS-20), Facial Emotion Identification Test (FEIT), the awareness of Social Inference Test (TASIT), temperament and Character Inventory (TCI), Interpersonal Reactivity Index (IRI), Symptoms Checklist-90 (SCL-90). The two clinical groups showed differences in TAS, FEIT and TASIT, highlighting Alexythimic tracts, difficulty in recognizing emotions and deficit of social inference, compared to HCs. The TCI and SCL-90 have also highlighted the common psychopathological characteristics and temperamental in patients with ED and SAD. Alexythimia is particularly represented in patients with ED and SAD, and could represent a maintenance factor, together with deficits in emotions recognition and social inference. The similarities between ED and TD seem to suggest the possibility of shared core features.