We describe a case of a 9‐year‐old child who presented with uncontrollable, involuntary movements associated with a recent streptococcal infection and echocardiographic evidence of valvulitis. These findings are consistent with the diagnosis of Sydenham's chorea, a rare but important movement disorder and one of the major “Jones criteria” for the diagnosis of acute rheumatic fever. Because of its rarity, patients with Sydenham's chorea often are misdiagnosed as having a behavioral or psychiatric illness. Early recognition and appropriate management can prevent the potential severe sequelae associated with acute rheumatic fever.