Human leukocyte antigen (HLA) typing was performed on 27 white patients with acute retinal necrosis syndrome. Antigens for the HLA-A, -B, -C, -DR and -DQ loci were determined, and frequencies were compared with racially matched controls. There was a statistically significant increase in the frequency of HLA-DQw7 (11 of 20 [55%] of patients vs 294 of 1546 [19%] of controls, P = .0004, relative risk 5.20) that remained significant at the P = .05 level when the P value was multiplied by the number of antigens tested. The HLA phenotype Bw62, DR4 is also more frequent than in normal control populations (4 of 25 [16%] of patients vs 26 of 1023 [2.6%] of controls, relative risk 7.49). These results support an association between the acute retinal necrosis syndrome and certain HLA specificities and suggest a possible immunogenetic predisposition to the syndrome in some patients.