There are three types of cardiomyopathy: hypertrophic, dilated and restrictive. The diagnosis and prognosis of these three types may be assessed from Doppler echocardiographic data. In hypertrophic cardiomyopathy, the diagnostic criterion is parietal hypertrophy. This hypertrophy is asymmetrical and usually affects the interventricular septum. Ventricular outflow obstruction is not necessarily present. The left ventricle is small and analysis of mitral inflow usually shows abnormal relaxation (E/A ratio < 1). The prognosis of this type of cardiomyopathy seems to be related to ventricular arrhythmias and the relationship between the hypertrophy and the presence of arrhythmias remains controversial. Dilated cardiomyopathy is characterized by ventricular walls of normal or decreased thickness, an increase in left ventricular dimensions and a reduction in the ejection fraction. An end-diastolic left ventricular dimension > 70 mm and an ejection fraction < 25% are poor prognostic factors. Left ventricular filling is abnormal and severe cases show a restrictive type of profile; in this case, an E/A ratio > 2 carries a poor prognostic. A mitral deceleration time of E wave < 150 msec usually indicates a bad outcome. Restrictive types of cardiomyopathy are more rare, amyloidosis being the commonest cause. Symmetrical wall thickening and a small ventricular chamber are observed. In advanced stages with abnormal systolic function, an E/A mitral ratio > 2 and deceleration time < 150 msec, the outcome is rapidly fatal.