Ninety eight patients with uveitis of various types were tested for the presence of the antineutrophil antibody or ANCA by an indirect immunofluorescence method. This antibody is found in patients with diseases associated with small vessel vasculitis, including Wegener's granulomatosis and microscopic polyarteritis. Eleven true positive cases were found. A positive test was not associated with the anatomical site of the uveitis but was related to the time course of the disease. In particular single/repeated rather than nonrecurrent uveitis was associated with a positive test. Three groups of patients seem more likely to have positive tests: those with bilateral chronic posterior uveitis; a group with an anterior uveitis which is single/repeated who were younger than 46 at disease onset and had isolated eye disease; and an older group, aged 60 years or more at onset, with single/repeated uveitis and systemic features.