Severe bradycardia is an indication supporting hospitalization in adolescents with eating disorders. Some adolescents with anorexia nervosa (AN) and significant weight loss present with a normal pulse rate at admission, whereas others have severe bradycardia, suggesting that total weight loss is not the most important determinant of bradycardia. The aims of this study were: to define the prevalence of severe bradycardia as the cause for hospital admission in adolescents with AN; to evaluate correlations between known determinants of severe bradycardia and pulse rate at admission; to evaluate the average time required to recover from severe bradycardia after re-feeding.