Natural regulatory T (nTreg) cells are described by expression of a specific transcription factor, FOXP3, on CD4+CD25+ cells. They play very important roles in the suppression of allergic reactions and disorders. The aim of this study was to obtain peripheral blood Treg levels among atopic asthmatic patients before and during inhaled steroid treatment and to observe the effect of these cells on the pathogenesis and treatment of asthma. CD4+CD25+FOXP3+ T cells obtained from 20 healthy donors and from 16 atopic asthmatic patients before and after inhaled glucocorticoid treatment were examined by flow cytometer. The levels of CD4+CD25+ FOXP3+ Treg cells were higher in asthmatic children who had been receiving inhaled glucocorticoids, when compared to the control group and to the patients' levels before treatment (p<0.05). The present study suggests that at least one of the anti-inflammatory effects of inhaled glucocorticoids in asthma depends upon induction of Treg cells.