AIM The purpose of this study is to evaluate echocardiographically determined cardiac functions with serum levels of brain natriuretic peptide (BNP), cardiac troponin I (cTnI) and total antioxidant status (TAOS) in childhood leukemia treated with chemotherapeutics containing anthracyclines. METHODS A study group of 29 patients who have been followed for acute lymphoblastic leukemia (ALL) and administered a treatment protocol containing chemotherapy of anthracyclines were included in the analysis. Levels of BNP, cTnI and TAOS were studied in serum samples of the patients. RESULTS We demonstrated that as the drug dosage increased, systolic ejection fraction (EF) and shortening fraction (FS) values decreased (EF r2=0.2327, FS r2=0.251). On the other hand, increased dosage of anthracycline therapy was associated with significant raise in plasma BNP levels (r2=0.246) and significant decrease in serum TAOS levels (r2=0.317) without any change in serum cTnI levels. CONCLUSION Our study suggest that serum TAOS and BNP levels may be useful as an early and sensitive indicator of anthracycline induced cardiotoxicity.