History and Objective: Due to the increasing prevalence of asthma and its known complication and the existing controversies about the correlation of IgE level and disease severity and in order to define the serum IgE Level and this correlation, this study was performed on referrers to educational hospitals of Iran University of Medical Sciences in 1373.

Materials and Methods: This study was performed by cross sectional method. The diagnosis of asthma and the management of asthmatic patients were according to standard. Smokers, patients with parasitic infestation and patients affected by pulmonary diseases other than asthma were excluded from the study. Normal serum IgE Level on blood samples was defined by ELISA method. Values less than 200 were considered as normal. Disease severity was classified as mild (Less than 50 episodes per year), moderate (Between 50 to 300 episodes per year) and severe (More than 300 episodes per year) and by using descriptive statistics relationship between serum IgE Level and disease severity and atopic manifestations were described.

Results: 101 patients were evaluated during the mentioned period. In 58% of the serum IgE Level was abnormally elevated and serum IgE level correlated with disease severity and presence of urticaria. There was no correlation between serum IgE Level from one side and atopic manifestations, cough, sputum, dyspnea and nocturnal asthmatic attacks from the other side. PEFR was less than 50% in 60% of cases. There was an inverse relationship between the length of the disease and the pulmonary function. Serum IgE Level correlated with PEFR.

Conclusion: There is an inverse relationship between serum IgE Level and pulmonary function but there is no relationship between serum IgE level and clinical manifestation.