Since 1944, the Jones criteria for the diagnosis of acute rheumatic fever have been regularly revised to integrate technical and diagnostic innovations. Echographic and Doppler criteria, however, remain unrecognised due to valvular insufficiency in healthy subjects. The aim of this study was to determine the cardiac lesions occurring in acute rheumatic fever and the diagnostic value of Doppler echocardiography. One hundred patients with an average age of 10 years were admitted to hospital because of a first attack of acute rheumatic fever between January 1991 and September 1992. Eighty-six had articular signs, 5 had chorea, but none had cutaneous lesions. Forty-seven murmurs of mitral insufficiency (MI) and eight of aortic insufficiency (AI) were detected; 10 children had signs of cardiac failure. Conduction defects were recorded in 12 cases. Echocardiography showed 7 pericardial effusions; often, the left heart chambers were dilated without alteration of the fractional shortening. The commonest lesions of the mitral valve were thickening of the two leaflets, the reduced mobility of the posterior leaflet, the rigidity of the anterior leaflet and 2 cases of ruptured chordae tendinae. The Doppler mode showed 73 cases of MI, 26 of which were at least moderately severe. These cases of MI were commonly excentric jets behind the posterior leaflet. There were 47 cases of AI, 10 of which were at least moderately severe. If all cases of moderately severe or mild AI and MI are considered as pathological when associated with suggestive morphological valve changes, the number of cases of carditis increased from 50 without the Doppler mode to over 80 with this mode. Doppler echocardiography validated the Jones criteria in 16 children. The authors propose Doppler echocardiography criteria for the validation of carditis.