Coeliac disease (CD) is a chronic inflammatory disorder where dietary gluten is not tolerated. In the lesion there are gluten reactive T cells predominantly secreting gamma-interferon. Both HLA and non-HLA genes contribute to CD susceptibility. Interleukin-12 (IL-12) regulates gamma-interferon production. The IL12B gene is located in a region (5q31.1-33.1) where there is evidence for linkage with CD. Allele 1 of an IL12B 3'UTR single-nucleotide polymorphism leads to increased expression of IL-12, and was recently implicated in susceptibility for type 1 diabetes (T1D). We found no evidence for association of allele 1 to CD by the transmission/disequilibrium test or case-control approach. No increased frequency was observed in patients belonging to families where the disease was linked to markers on chromosome 5q. Unlike T1D, allele 1 does not appear to confer susceptibility to CD.