Background: Bronchial asthma is a known chronic inflammatory disease. Asthma is categorized into atopic asthma and non-atopic asthma based on absence or presence of atopy which is a positive skin prick test 3 mm or Immunoglobulin E (IgE) specific antibodies that are produced against common allergens. Oxidative stress has a role in pathogenesis of bronchial asthma. Clusterin is a glycoprotein chemokine and has a role in recruitment of inflammatory cells. Aim of the Work: Our aim was to measure serum level of Clusterin in bronchial asthma patients including both (atopic and non-atopic) and to correlate it with the severity of the disease. Materials and Methods: Case control study was done on (96) adult patients diagnosed with bronchial asthma (64 atopic and 32 nonatopic), in addition to (32) sex and age matched healthy controls. Serum Clusterin & IgE levels were measured using enzyme linked immunoassay. Results: Clusterin level was higher in atopic and non-atopic patients' groups when each was compared to control group (p<0.01, respectively). Clusterin was elevated in severe atopic asthma compared to mild and moderate atopic patients (p=0.002 and 0.003, respectively). Clusterin was elevated in moderate non atopic asthma compared to mild non atopic patients (p=0.021). Multi-ROC of IgE and Clusterin at 23 IU/mL (IgE) and 20 ng/mL (Clusterin) showed diagnostic performance efficacy (98.4%) to differentiate between control and non-atopic group. Clusterin 10 ng/mL & total IgE 125 IU/mL discriminate severe cases of bronchial asthma versus mild and moderate cases of bronchial asthma. Conclusion: Our study revealed that serum Clusterin can be a promising marker in diagnosis of bronchial asthma, and detection of degree of severity.