Asthma results from the interaction between genetic and environmental factors. ADAM33 gene on chromosome 20p13 is associated with asthma and airway hyperresponsiveness.This is a case-control study, where four SNPs S1 (rs3918396), T1 (rs2280091), T2 (rs2280090), V4 (rs2787094) of ADAM33 gene have been assessed in patients with allergic asthma and normal controls (95 patients and 86 normal). Blood samples of these participants have been genotyped by PCR and the RFLP method.There was no association between asthmatic patients and polymorphisms of alleles, genotypes and haplotypes of the ADAM33 gene. When categorizing the asthmatic patients in severe, moderate and mild groups, associations in the subcategories of asthmatic patients were found. There were associations between polymorphisms of C allele of T1 SNP with severe asthmatic patients and G allele of V4 SNP with moderate asthmatics respectively (P=0.006, P=0.01). There was a significant association between sensitivity to mite and polymorphism of C allele of T1 SNP (P=0.02). Besides, there was a significant association between sensitivity to weeds and genotype GG of V4 SNP (P=0.05).Polymorphisms of ADAM33 gene might be associated with severe asthma and sensitivity to aeroallergens in northeast of Iran, but further studies are needed to determine the polymorphisms in this area and other regions of our country.