After adjusting for age, BMI, gender, and ancestral information, many rare haplotypes of IL1RN tagging SNPs rs2234678-rs392503-rs1794067-rs973635-rs440286 (e.g., GGAGA) had protective effect for asthma relative to the more common haplotype AAGGC in either the overall population or subjects without childhood ETS exposure. This evidence concerns the gene IL1RN and asthma.