Using Doppler echocardiography, we studied the left ventricular systolic and diastolic function in 124 healthy control children (group C), 110 oncology patients who had received anthracycline (group A), and 76 oncology patients who had received chemotherapy not including anthracycline (group N), at rest and after supine bicycle exercise. The mean dosage of anthracycline that group A patients received was 219 +/- 95 mg/m2. Impaired systolic function was detected in 29% of the patients in group A and 4% in group N. Figures for impaired diastolic function for group A and N were 27% and 28% respectively. Abnormal diastolic function was detected more frequently in the first two years after chemotherapy in both groups. Four parameters measured at rest appeared to be specifically abnormal in group A but not in group N. These were ejection fraction, fractional shortening, rate-corrected velocity of circumferential fiber shortening (VCFC) and left ventricle peak systolic wall stress (LVWS). After exercise more parameters were abnormal in group N patients when compared to normal children, but abnormalities of VCFC and LVWS remained specific for group A. In conclusion, abnormalities of diastolic function were common among paediatric oncology patients no matter whether they had received anthracycline treatment or not. Abnormalities of systolic function were more specific to anthracycline toxicity. VCFC and LVWS were the most sensitive measurements for differentiating group N patients from group A patients.