Between 1995 and 2001 echo-cardiography was performed in 244 children (128 boys, 116 girls) with acute lymphoblastic leukaemia (ALL) before the beginning of therapy with anthracyclines (medium 5.4 days after the diagnosis). The mean age at diagnosis was 5.4 years (range 9 months to 17.7 years). 189 children (97 boys and 92 girls) were included into the standard and medium risk groups and 55 (31 boys and 24 girls) into the high risk group. 29% of ALL children had disturbances in ECG. Changes in the thickness of the intraventricular septum (%IVSTh) and left ventricular posterior wall (%LVPWTh) were statistically lower, especially in children under 7 years of age. Some children showed lowering of shortening fraction (%FS - 8.6%), ejection fraction (%EF - 10.2%) and corrected velocity of fibber-shortening (Vcfc - 25.8%). Children with decreased shortening fraction (%FS) had left ventricular posterior wall thickness (%LVPWTh) impairment. Changes in diastolic function indicate impaired relaxation and compliance of the left ventricle. Decreased peak early filling velocity (E) was found. There were also longer deceleration time (EDecT) and decreased deceleration from peak E velocity (E/Dec) and longer isovolumetric relaxation time in children in standard and medium risk groups. Shorter acceleration time (EAccT) was seen in the high risk group. Evaluation of cardiac function before anthracycline chemotherapy will allow to select patients with pre-existing cardiac impairment for whom cardioprotective treatment is absolutely necessary.