Population distribution and pathogenetic significance for bronchial asthma (BA) of the eight polymorphic variants of six interleukin--(IL) and interleukin receptor genes, C-589T, G/C 3'-UTR IL4, C-703T IL5, T113M IL9, Q551R, 150V IL4RA, and G1972A IL5RB, was examined. In the population samples of Russians, Tajiks, Buryats, and Tuvinians racial and ethnic specificity of these polymorphisms was established. These specific features were manifested as population-specific "enetic portraits" in respect of polymorphic allele frequencies. Analysis of the BA patients and their relatives from Tomsk by use of transmission/disequilibrium test (TDT) revealed the presence of a statistically significant association between the C-703 IL5 allele and the disease (P = 0.005). This is the first evidence of an association between the IL5 gene polymorphism and BA.