The aim of this study was to evaluate N-terminal probrain natriuretic peptides (NT-pro-BNP), cardiac troponin T, and creatinine kinase, MB isoenzyme (CK-MB) in the determination of subclinical left ventricular (LV) dysfunction by echocardiography in patients treated with doxorubicin. We performed a cross-sectional case study of systolic, diastolic function and tissue Doppler imaging by echocardiography in children with cancer who received a certain cumulative dose of doxorubicin. Blood levels for NT-pro-BNP, cardiac troponin T, and CK-MB were analyzed within 6 hours of the cardiac study. Of 30 patients, 5 (16.7%) had LV dysfunction with an abnormally high NT-pro-BNP level of 363 ± 78 pg/mL, whereas patients with normal LV function had an NT-pro-BNP level of 148 ± 173 pg/mL (P = 0.012). The NT-pro-BNP level not only inversely correlated with fractional shortening (r = -0.43, P = 0.017) and ejection fraction (r = - 0.45, P = 0.013) but also correlated with mitral deceleration time ( r = 0.41, P = 0.021) and a cumulative dose of doxorubicin (r = 0.44, P = 0.014). For tissue Doppler imaging, NT-pro-BNP correlated with a peak systolic velocity at the myocardial segment (Sm) (r = -0.40, P = 0.027). NT-pro-BNP is a sensitive test and has a moderate relationship with the LV systolic and diastolic function, thus making it a useful cardiac marker for the monitoring of early anthracycline cardiotoxicity.