Abstract. Multiple sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system that causes neurological disorders in young adults. Previous studies in various populations highlighted an association between the Hla-drB1 * 15 allele and MS. This study investigated the association between Hla-drB1 * 15 and other Hla-drB1 alleles and MS in a Brazilian caucasian population sample from londrina, Southern Brazil. Hla-drB1 alleles were analyzed by polymerase chain reaction with specific sequence oligonucleotide primers in 119 MS patients and in 305 healthy blood donors as a control. among the MS patients, 89 (75.0%) presented with relapsing remitting MS, 24 (20.0%) with secondary progressive MS and 6 (5.0%) with primary progressive MS. The frequency of the Hla-drB1 * 15 allele observed in the MS Brazilian patients was similar to findings reported in previous studies carried out in populations worldwide. However, the results showed a higher frequency of the Hla-drB1 * 15 allele in the MS patients compared to the controls, with a relative frequency of 0.1050 (10.50%) and 0.0443 (4.4%), respectively (or=2.53; 95% ci 1.43-4.46; p=0.0009). a protector allele was also detected. The frequency of the Hla-drB1 * 11 allele was reduced in the MS patients compared to the controls, with a relative frequency of 0.1345 (13.4%) and 0.1869 (18.7%), respectively (or=0.67; 95% ci 0.44-1.03; p=0.0692). The results demonstrated that the Hla-drB1 * 15 allele in heterozygosity is positively associated with MS (p=0.0079), and may be considered a genetic marker of susceptibility to the disease. a negative association between the Hla-drB1 * 11 allele in homozygosity and MS was also verified (p=0.0418); this allele may be considered a genetic marker of resistance to MS in the Brazilian population.