Background. The therapeutic potential of anthracycline antibiotics is limited by their cardiotoxicity. Electrocardiography, exercise testing, and two-dimensional echocardiography are non-invasive techniques used in the followup of children for cardiotoxicity. Plasma B-type natriuretic peptide (BNP) levels are thought to be useful markers in the early detection of AC induced cardiomyopathy. Procedure. We evaluated cardiac status of 34 patients with solid tumors treated with anthracycline antibiotics. All of the patients were asymptomatic and had no evidence of residual malignancy. They were evaluated by electrocardiography, exercise testing, echocardiography, and plasma BNP levels measured before and after the exercise testing. Results. Electrocardiography revealed only minor abnormalities of little clinical significance. All of the patients completed the exercise testing without complication, and the duration of the exercise for each patient was between normal limits. Cardiac output (CO) and wall stress (WS) were significantly increased in patients, than in controls in echocardiographic evaluation of systolic functions (P < 0.001). Diastolic filling patterns showed various abnormalities; M-E, MA T-E, T-A, AT, and IVRT were significantly higher than those of controls. Mean plasma BNP levels of the patients (10.56 +/- 10.22 pg/rnl) were significantly higher than BNP levels of the healthy controls (4.09 +/- 2.26 pg/ml) (P < 0.016), before exercise testing. The mean plasma BNP levels of the patients (15.70 +/- 14.06 pg/ml) were higher than resting state after exercise testing, but it was not statistically significant (P > 0.05). Conclusion. Our findings demonstrated that echocardiographic and biochemical abnormalities could be found even at low cumulative doses of AC antibiotics. The use of serial echocardiographic studies and plasma BNP determinations to identify high-risk patients for cardiotoxicity needs to be verified by additional Studies. (C) 2004 Wiley-Liss, Inc.