Asthma is a chronic inflammatory disease of the airway. Pathological repair of chronic inflammation leads to airway remodeling. Transforming growth factor-beta (TGF-beta), a profibrotic cytokine, plays an important role in promoting the structural changes of airway remodeling. TGF-beta effects on the proliferation, differentiation and extracellular matrix (ECM) metabolism of airway structural cells. This study assessed serum TGF-beta1 in different severity of atopic asthma compared to non-atopic controls. Thirty-one atopic asthmatic patients and 34 non-atopic controls, aged 7-18 years, were recruited as to the asthma severity: steroid naïve mild asthma, moderate asthma, and asthma in remission. Serum TGF-beta1 was measured by enzyme-linked immunosorbent assay. There was a significant difference between serum TGF-beta1 in asthmatic patients and that in control patients (39.59 ng/ml vs. 0.26 ng/ml, p < 0.001). Serum TGF-beta1 was highest in steroid naïve mild asthma group when compared to the moderate asthma and asthma in remission groups (47.44 ng/ml vs. 38.64 ng/ml and 47.44 ng/ml vs. 35.94 ng/ml, p = 0.013 and 0.001, respectively). There were no correlations among serum TGF-beta1 and pulmonary function test parameters, duration of asthma, and duration of inhaled corticosteroid treatment. These data support the role of TGF-beta1 in airway remodeling in asthma.