Asthma is a major cause of chronic morbidity and mortality throughout the world and there is evidence that its prevalence has increased considerably over the past 20 years, especially in children. Fortunately, asthma can be effectively treated and most patients can achieve good control of their disease. When asthma is under control patients can: avoid troublesome symptoms night and day, have (near) normal lung function and avoid serious attacks (GINA, 2010).Th1/Th2 responses are induced by antigen-specific effector and memory Th1/Th2 cells (Toshinori and Masakatsu, 2008). The conventional definition of a Th1 or Th2 cell depends strictly on the secretion of IFN-γ or IL4. Th1 cells secrete IFN-γ but do not secrete IL4, whereas Th2 cells secrete IL4 but not IFN-γ. (Monteleone et al, 2005). LTB4 is a potent chemoattractant for neutrophils and considered to play a role in various inflammatory responses (Mita, et al. 2007) and it is associated with multiple inflammatory pathologic conditions, including asthma (Cybulsky, et al., 2001).The aim of the present study is to assess Th1/Th2 balance in asthmatic children, represented by serum level of IFN-γ and IL-4 respectively, and to correlate this ratio with asthma severity. Also to assess Th1/Th2 changes with different therapies (ICS and LTA). And finally to assess the value of using the urinary leukotrienes as an inflammatory marker and to evaluate the effect of inhaled glucocorticosteroids and the leukotrienes antagonists on its level.