The distribution of HLA class II alleles in Guillain-Barré syndrome (GBS) has previously been reported only for HLA-DR. We report here the results of genomic typing for HLA-DR, -DQ and -DP allelic variability by restriction fragment length polymorphism analysis in 49 patients with a history of GBS. No association was found to HLA-DR, -DQ or -DP alleles or HLA-DR-DQ haplotypes. Subgrouping of patients according to severity of disease, as measured by disability or muscular weakness, or response to plasmapheresis treatment, also failed to reveal significant associations. These data suggest that HLA class II genes do not confer susceptibility to GBS.