We describe the clinical features of idiopathic restrictive cardiomyopathy in a female infant. A marked elevation of left ventricular end-diastolic pressure, and profoundly abnormal myocardial relaxation, were detected with the use of Doppler blood flow echocardiography, coupled with the relatively new technique of Doppler tissue echocardiography. There was no clinical evidence of ongoing heart failure, but she had signs of myocardial ischaemia, and unfortunately died suddenly at the age of 13 months.