HLA typing for A, B, and C locus antigens was performed on 70 patients with ocular cicatricial pemphigoid (OCP) and on 1849 controls. Additionally, typing for DR and DQ antigens and for the complement proteins (C2, factor B, C4A, and C4B) was performed on 63 patients and on the same control population. A significantly higher incidence of the following antigens was found in the OCP patients when compared to the control population: DR4 (43% in patients compared to 18% in controls, p = 0.0001); DR5 (41% compared to 16%, p = 0.0001); DQw3 (57% compared to 31%, p = 0.0010); A2 (60% compared to 28%, p = 0.0001); B8 (24% compared to 13%, p = 0.0086); B35 (19% compared to 9%, p = 0.0097); and B49 (7% compared to 2%, p = 0.0052). The complement types SC01, SC30, SC32, SC41, and SC42 were also significantly increased in patients compared to controls. No significant differences were found based on ethnic background, involvement of multiple mucous membranes, history of glaucoma, or deposition of specific immunoreactants in conjunctival biopsy samples. These findings may provide further insights into the pathogenesis of OCP and may help to localize a susceptibility gene for this autoimmune disease.