Scleritis is a condition of the eye often associated with systemic diseases, allergy and infections. Nomoto et al. have reported the frequency of episcleritis in patients with IgA nephropathy (Berger's disease), a primary glomerulonephritis initially described by Berger in 1968. It is characterized by mesangial deposits of IgA, and is considered one of the most frequent nephritides in France. We report our study of the association of scleritis with glomerulonephritis (GN). Fifty-three GN patients were examined for the presence of scleritis. The exact type of nephropathy in each patient was determined by a renal biopsy and immunofluorescence studies. Episcleritis was found in 10 GN patients: in 5 out of 27 Berger's disease, 3 out of 4 patients with isolated mesangial C3 deposits, 1 out of 2 patients with membraneous GN, and 1 out of 5 patients with membranoproliferative GN. The finding of episcleritis in 18% of patients with IgA nephropathy is very similar to the results reported by Nomoto et al. (15%). As no other cause of episcleritis was found in these positive patients, the ocular lesion may be considered to be related to their GN. Episcleritis patient had no abnormal levels of serum IgA, but circulating immune complexes activating the alternate pathway of the complement system were present in most of them. In one female patient with Berger's disease and frequent episodes of episcleritis, an episcleral biopsy was obtained for immunohistological studies. Large numbers of dimeric IgA secreting plasma cells were observed in this tissue. These results suggest the involvement of ocular surface immunity in some cases of IgA nephropathy. It might therefore be useful to investigate the renal function of patients presenting recurrent episodes of episcleritis.