In coeliac disease (CD) a profile of proinflammatory cytokines are secreted interferon gamma (IFNgamma) being one of the most important. A dinucleotide polymorphism consisting of a variable number of CA repeats related with IFNgamma production levels, has been reported on the first intron of the IFNgamma gene. The aim of this study was to analyse the influence of the functional IFNgamma CA repeats in CD predisposition through familial and case-control studies. The familial analysis showed that the 124 bp allele was significantly more transmitted to the affected offspring (P=0.02), while the 126 bp allele showed a statistically significant nontransmission pattern (P=0.01). Nevertheless, in the case-control analysis, we could not find a direct association of CA repeats with CD. This fact might be due to parent-of-origin effect in the IFNgamma CA polymorphism. Our data suggest a possible role of IFNgamma CA polymorphism in CD susceptibility.