Background and Objective: Asthma is a common respiratory disease caused by acute and chronic bronchial inflammation. Clinical manifestations of the disease are closely related to genetics. IL-4 is a cytokine of TH2 lymphocytes, polymorphism in prompter region, C-589T, is associated with IL-4 production, while IFN-γ, is a cytokine of TH1, and A+874T polymorphism in interon 1 of IFN-γ is associated with it’s production and release. Cytokine gene polymorphisms could influence pathogenesis of asthma with TH1/THh2 ratio, being of great importance. Materials and Methods: 81 unrelated asthmatic patients were selected according to ATS characteristics and separated into two groups of controlled and uncontrolled asthma. 80 normal subjects were chosen as control group. After collection of peripheral blood and DNA extraction, PCR-RFLP method was used for genotyping of IL-4, -589 position. For evaluation of polymorphism in +874 position of IFN-γ ARMS-PCR method was used. Results: Distribution of frequency of IFN- (A+874T) and IL-4(C-589T) polymorphisms didn’t show any statistically significant difference between two patient groups and healthy control group (p≥0.05). There was neither any significant difference (p≥0.05) among other parameters. Conclusions: Studies in field of cytokine polymorphism have had variable results. So many studies have mentioned a relationship between cytokine gene polymorphism and susceptibility and/or severity of asthma and some studies have shown that there is no association between these factors we believe that there may exist factors different from IL-4 and IFN-γ polymorphism which coner the effects of these genetic vaciants in pathogenesis and severity of asthma.