HLA-A, HLA-B, and HLA-C antigens were typed on 48 patients with recurrent herpes stromal keratitis. The HLA-Aw30 antigen occurred three times more frequently in patients with herpes stromal keratitis than in those who lack the Aw30 antigen. When the data for the probability of the HLA-Aw30 were corrected for the number of variables studied, the corrected P value was not significant. A previous report of an increased frequency of HLA-B5 with recurrent herpes keratitis was not confirmed by our study. No significant associations with the HLA-C antigens were noted. HLA-DR antigen typing of 25 herpes stromal keratitis patients indicated that the HLA-DRw3 antigen appeared to have an increased frequency in herpes stromal keratitis. However, the small sample size studied precluded interpretation of the increased phenotypic frequency and the possible association of HLA-DRw3 and herpes stromal keratitis needs further study.