This is a retrospective study of the treatment of eight female patients with Sydenham's chorea by corticosteroid administration. The rationale for use of this medication is based on the concept that Sydenham's chorea is caused by an indolent inflammation of the small vessels in the caudate-putamen complex. All patients in this series responded to corticosteroid treatment relatively rapidly, with considerable diminution in abnormal movements. It is concluded that corticosteroid treatment of this condition is effective and deserves wider use. This report should serve as an impetus for more controlled studies.