We investigated the possible association of IBD with C1672T of SLC22A4 and G-207C of SLC22A5 alleles, and with the novel IGR2096a_1 (rs12521868) and IGR2198a_1 (rs11739135) susceptibility loci, all located on IBD5 locus of chromosome 5q31.DNA of 217 Crohn's disease, 252 ulcerative colitis, and 290 control patients were analyzed by polymerase chain reaction/restriction fragment length polymorphism methods.Neither the C1672T and G-207C alleles, nor the TC haplotype were found to be risk factors. By contrast, the minor allele frequencies of IGR2096a_1 T (47.2%) and IGR2198a_1 C (45.9%) were increased in Crohn's disease compared with the controls (38.2% and 37.7%, respectively; p < 0.05); multivariate regression analysis revealed a risk nature for Crohn's disease (OR = 1.748, 95% CI 1.186-2.574; p = 0.007 for T allele, OR = 1.646, 95% CI 1.119-2.423, p = 0.011 for C allele of IGRs).The data suggest a special haplotype arrangement of susceptibility genes at the IBD5 locus in Hungarians, which nation differs historically from the surrounding Caucasian ethnicities in its origin.