Sydenham's chorea (SC), a major manifestation of acute rheumatic fever (RF), is characterized by chorea and other motor and non-motor features. Among the latter are behavioral symptoms, including obsessive-compulsive disorder. Although SC is typically a self-limited condition, up to 50% of patients may evolve with persistent chorea. There is evidence that Gustav Mahler had a movement disorder, but its nature remains undetermined. There are witnesses describing him as having facial dyskinesia and a gait disorder consistent with chorea. His conducting performance was notorious for obsessive attention to details of the staging and musical production. Mahler was diagnosed with a valvulopathy in 1907 and died of subacute bacterial endocarditis in 1911. It is possible that the composer suffered from RF in childhood with carditis and SC, which may left him with valvulopathy, obsessive-compulsive disorder, and persistent chorea.