The HLA antigen distribution was studied in 37 north Indian patients with myasthenia gravis. The control group consisted of 118 normal, healthy individuals of the same ethnic group. The antigens showing the highest frequency were Bw21 (18.9% vs 4.2% p less than 0.005), Bw35 (24.3% vs 6.8%, p less than 0.005) and A9 (51.3% vs 30.5%, p less than 0.025). HLA-B8 was increased nearly two fold in the myasthenia gravis patients (RR = 2.4) and was confined mainly to the young females without thymoma. The possibility that Bw21 and Bw35 might be the markers for susceptibility to autoimmune disorders in India is discussed. The observations also support those of others that HLA-B8 linked susceptibility gene is more frequently found in myasthenia gravis patients with thymic hyperplasia.