Eating disorders (EDs) are among the most lethal psychiatric disorders and are characterized by a wide range of physical comorbidities. Most are complications of the behavioral symptoms of each ED, such as malnutrition in anorexia nervosa (AN), hydro-electrolyte imbalance and digestive lesions in bulimia nervosa (BN), and metabolic syndrome in binge eating disorder (BED). Other comorbidities may be primary or difficult to disentangle from the pathogenesis of EDs, such as functional intestinal disorders. In some cases, the two comorbidities may interact or exacerbate each other, worsening the prognosis. A discrete number of patients present with comorbidities even before seeking specialist care for ED, so it is important for clinicians to carry out appropriate screening as soon as an ED is suspected. Many comorbidities can be reversed by treatment of the specific ED. For example, nutritional support can reverse most complications of AN. Multidisciplinary management is the rule, allowing fruitful collaboration between psychiatrists, physicians, nutritionists, and paramedical staff. This chapter describes the main somatic comorbidities and complications specific to AN, BN, and BED.