Regulated upon activation in normal T cells, expressed, and secreted (RANTES) protein is abundantly expressed during atopic asthma, suggesting that it is an important mediator of this disease. The aim of this study was to evaluate the possible role of RANTES promoter polymorphisms in children with asthma. We genotyped 271 children with atopic asthma, 55 children with nonatopic asthma, and 253 control children for allelic determinants at two polymorphic sites in the promoter region at positions -403G>A and -28C>G by restriction fragment length polymorphism methods. There was no significant difference in genotype and allele frequencies of the RANTES -403G>A and -28C>G polymorphisms when the atopic asthma, nonatopic asthma, and control groups were compared. However, atopic asthmatic patients who were homozygous GG for the RANTES -28C>G tended to have lower PC20 methacholine than those carrying the wild genotype. In addition, a significantly lower PC20 was demonstrated for the homozygous haplotype -403A/-28G in asthmatic children. The polymorphisms within the RANTES promoter may have a disease-modifying effect in Korean children with asthma.