Guillain-Barré syndrome (GBS) is the prototype of a postinfectious autoimmune neuropathy. Molecular mimicry between glycolipid antigens expressed by an infective antigen such as Campylobacter jejuni and the human peripheral nerve has been hypothesized to be the causative mechanism of GBS. However, only 1/1000 of C. jejuni enteritis develops GBS. This emphasizes the importance of host-related factors in the development of the disease. HLA studies in GBS failed to show an association or gave conflicting results but MHC class I and II process and present peptides to T lymphocytes making unlikely that the HLA system plays a role in GBS with autoantibodies against self-gangliosides. CD1 molecules are MCH-like glycoproteins specialized in capturing and presenting a variety of glycolipid to antigen-specific T cells. There are five closely linked CD1 genes in humans located in chromosome 1 (named CD1A, B, C, D, and E) all showing limited polymorphism in exon 2 which codifies for the alpha1 domain of CD1 molecules. The nucleotide substitutions in CD1B and CD1C are rare and reported to be silent. In 100 controls and 65 GBS patients (21 with a recent C. jejuni infection and 35 with anti-glycolipid antibodies) we used direct sequencing by polymerase chain reaction to genotype exon 2 of CD1A, CD1D and CD1E genes. CD1D is monomorphic in both controls and patients whereas CD1A and CD1E are biallelic in exon 2. Subjects with CD1E*01/01 genotype are 2.5 times more likely to develop GBS, whereas subjects with CD1A*01/02 or CD1E*01/02 have a reduced relative risk by 3.6 and 2.3 times respectively. The combination of CD1A*01/02 and CD1E*01/02 reduces by 5 times the risk of developing GBS. Although a correlation between CD1E*01/01 genotype and recent C. jejuni infection or presence of antiganglioside antibodies was not found the overall findings indicate that susceptibility to develop GBS is associated with polymorphisms of CD1E and CD1A genes.