The early onset of isolated aortic incompetence in a male child with HLA B27 and peripheral arthritis is reported. Acute anterior uveitis and lone aortic incompetence occurred at 1 and 9 months respectively after the development of the acute inflammatory arthritis. The uveitis resolved with local therapy and the arthritis remitted 10 months after the onset. There has been no recurrence of the arthritis after 10 years of close follow-up but the aortic incompetence has persisted, though it remains haemodynamically insignificant.