We evaluated the echocardiographic features of 69 children diagnosed with Sydenham's chorea at the first attack of acute rheumatic fever. By echocardiography, carditis was detected in 71% of cases and silent carditis was shown in 28.9% of cases at initial presentation. Most patients had mild or moderate valvular regurgitation. Sixty-three cases were followed from 1-10 years. The improvement rate in valvulitis in cases with silent carditis (29.4%) was not different than in cases with clinical carditis (18.5%) (p > 0.05). Persistence of valvular pathologies occurred in 72.2% of cases with carditis in the long-term follow-up (> 2 years). Most patients (88.8%) complied with secondary prophylaxis, so relapse of carditis was exclusively prevented in our patients. Recurrence of chorea was identified in 20.6% of cases and was not associated with clinical or laboratory evidence for streptococcal reinfection. Patients with chorea usually had mild carditis, and carditis showed resolution. Relapse of carditis in our population was exclusively prevented with secondary prophylaxis. Recurrence of chorea was not rare, despite regular treatment with benzathine penicillin.