Eighteen patients were examined by Doppler echocardiography before and after treatment with doxorubicin (DXR). Early left ventricular filling rate decreased from 66 +/- 15 to 51 +/- 10 cm/sec whereas late filling rate increased from 48 +/- 12 to 61 +/- 9 cm/sec (p less than 0.05) with inversion of the E/A ratio suggesting an impairment of left ventricular diastolic function; conversely no significant changes were found in systolic function indexes. These results suggest that follow-up of patients treated with DXR must include left ventricular diastolic function studies. Doppler echocardiography can be successfully used to detect the presence of diastolic abnormalities.