Between 1971-1988 we have studied 46 children with dilated cardiomyopathy. Twenty were males and 18 females, with a median age of 17 months (range from 1 day to 11 years). The incidence of 3.4 cases a year during the first nine years dropped to 1.3 cases a year in the following years. Two patients were siblings. Seventeen patients were studied with Eco-Doppler, cardiac catheterization and angiocardiography. The most frequent presentation was heart failure, present in 45 cases (98%). By bidimensional echocardiography it was observed that all patients had a dilated left ventricle, with a left atrial/aorta ratio of 1.5 +/- 0.3; the ejection fraction was diminished in 12 patients (11-36%) and the length of the left ventricle in the long parasternal axis view 4.2 +/- 0.7. All the patients studied had an elevated telediastolic pressure in the left ventricle, four with pulmonary artery pressure of 96 +/- 11 and seven with right atrial pressure of 24 +/- 5. There was mitral insufficiency in 4 patients and tricuspid insufficiency in three. Clinical course was favorable in 18 patients with median age at present of 112 months (range: 11 months to 15 years). The last 6 patients, treated with vasodilators, are living. In conclusion, dilated cardiomyopathy is a moderately frequent disease, with trend to diminish in incidence prognosis improved after treatment with vasodilator was introduced, and easily assessed with non-invasive methods.