Thirty-one patients with acute rheumatic carditis associated with aortic (AR) and mitral regurgitation (MR) who received corticosteroid anti-inflammatory therapy for an average of nine weeks were followed up for 332 patient-years (mean: 10.71 years). The age of onset was 9.34 (1 SD = +/- 1.94) years. The patients were classified according to degree of left ventricular volume overloading (LVH), duration of pre-treatment interval and regularity of penicillin prophylaxis. The probability of the yearly disappearance of MR, AR and both lesions were calculated for the total group and in relation to affecting subgroups. The mean yearly rate of disappearance of AR was 2 percent after a 10 percent probability in the first year. This rate was 6.83 percent per year for MR, and it increased to 10.15 percent per year in the patients in whom therapy was initiated in less than three weeks, and decreased to 3.14 percent in the patients in whom therapy was initiated after three weeks. The disappearance of both AR and MR was observed in only two patients (about 1% per year); MS developed in two patients (6.45%) and the mortality rate was 3.2 percent in 332 patient-years (0.0001/year).