Data on 33 Aboriginal children with rheumatic heart disease who attended the Royal Darwin Hospital over a four-year period were examined. Mitral-valve incompetence was the most-common valvular lesion that occurred as a result of rheumatic heart disease and was present in 30 children. Mitral stenosis was present in 17 children and was accompanied by incompetence in all cases; it was present by the age of 13 years in more than half the children. Five children died in the period of the study and four of these had mitral stenosis as part of their valvular abnormality. Rheumatic heart disease is a significant cause of morbidity and mortality in Aboriginal children in the Northern Territory.