Of 24 patients with familial acute anterior uveitis (AAU) 22 cases were non-granulomatous and 2 granulomatous. Of the 23 HLA tested patients 19 had the antigen HLA-B27. The 2 granulomatous and 2 non-granulomatous AAU cases were HLA-B27 negative. The iritis associated with the antigen HLA-B27 was unilateral, acute and recurrent, with cells and flare in the aqueous humor, and it lasted on an average 5 weeks. Keratic precipitates were never mutton fat, if the antigen B27 was present. X-ray examination of 8 patients revealed sacroilittis in 5. It is concluded that certain factors like trauma or infective agents may provoke familial AAU which is in close relationship with the HLA-B27 associated rheumatic group of diseases.