The association of HLA B8 and DR3 with generalised adult onset myasthenia gravis (GMG) in European Caucasoids is now well established. Studies of the HLA association with myasthenia gravis (MG) in other races might help to determine the location of a critical disease locus. Some previous studies in Japanese, Thais, Asian Indians and Filipinos have been reported. In this study HLA A, B, C and DR typing on 28 American blacks with either GMG or ocular myasthenia gravis (OMG) is reported. A significant increase in both HLA A1 and B8 was detected but there was an increase in DR5 rather than DR3. A review of the HLA antigen frequencies in other races and in D-penicillamine (D-Pen) induced MG suggests that prior claims implicating immune response genes marked by DR3 require review. It seems unlikely that any particular HLA allele is involved directly. Other possibly relevant combinations of alleles or supratypes are suggested. These may provide the basis for future studies of the immunogenetic basis for MG.