The aim of this study was to evaluate cardiac, biochemical and endocrine differences between female adolescents with anorexia nervosa (AN) with and without pericardial effusions. We studied 128 female adolescents (9.8-17.7 years) with anorexia nervosa (AN) diagnosed according to DSM-IV (American Psychiatric Association, 1994) criteria. They all underwent an echocardiographic evaluation. In 29 patients (22.2 %) a pericardial effusion (ranging between >or= 0.35-2.5 cm) was noted. None of the patients were clinically symptomatic. After 3 months of refeeding, the effusions disappeared in 18/29 patients while in 7/29 patients a pericardial effusion > 0.3 cm persisted. Risk factors for development of effusions were a BMI <or= 13,5 kg/m(2), weight loss >or= 25% and IGF-1-level <or=100 ng/ml. Pericardial effusions are common in adolescent AN patients. They are mostly asymptomatic not requiring any intervention and spontaneously regress with refeeding. They are more common in the patients with the most significant weight loss.