Acute rheumatic fever (ARF) is a well-characterized illness. However, syncope in ARF due to advanced heart block is very rare. A 10-year-old boy was admitted with recurrent syncope for 12 h. The patient was diagnosed as ARF because of arthritis, elevated acute phase reactants, advanced heart block, high antistreptolysin O titer, and echocardiographic evidence of mitral regurgitation. On the 9(th) day of hospitalization, the electrocardiogram revealed normal sinus rhythm.