Graves' disease (GD) is an autoimmune thyroid disease. Development of the disease phenotype is believed to be dependent on environmental factors and the action of several genes either in concert or in independent groups. Genes of, or closely associated to, the human leukocyte antigen (HLA) complex are important in determining genetic predisposition to GD in various ethnic groups. We previously reported that no significant HLA class I or -DR associations were detected in the total group of African-American patients with GD. To further investigate the associations of GD with HLA class II alleles, 52 unrelated African-American female patients with GD and 55 controls were typed for HLA-DRB1, -DQA1, and -DQB1, using sequence-specific oligonucleotide probes to analyze polymerase chain reaction amplified DNA. There were no significant differences in HLA distribution between patients and controls. These findings indicate that the contribution of HLA-DR and DQ regions to susceptibility to GD is small in African-American women.