Fifty consecutive patients with Friedreich's ataxia were examined to characterize their cardiac diastolic function. Electrocardiographic abnormalities were detected in 42 (80%) of the 50 patients. Echocardiography showed left ventricular hypertrophy in 14 patients (28%): concentric in 12 and asymmetric in 2. Left ventricular percent fractional shortening was normal in all except 2 patients. Diastolic filling characteristics measured from Doppler mitral flow velocity traces were not statistically different from those of 18 healthy control subjects. No abnormal diastolic flow pattern was observed in patients with left ventricular hypertrophy, whether concentric or asymmetric.