Background and purpose: The airway inflammation defining asthma is regulated by a network of interacting cytokines. The functional role of each individual cytokine in the immunopathogenesis of the disease remains controversial. Allergic diseases are based on to Th2 immune responses, which are characterized by high levels of proinflammatory interleukin (IL) IL-4, and a defective interferon-gamma (IFNγ) production, the principal Th1 effector cytokine. Materials and methods: I studied serum markers of allergic inflammation in 136 pediatric patients with wheezing and especially asthma (IL-4, IFNγ, serum eosinophils and total IgE), using commercially available ELISA kits. Results: I found an imbalance between serum levels of pro and antiinflamatory cytokines: higher levels of IL-4, in contrast with a lower production of IFNγ. Conclusions: The findings are relevant; the serum level of IL-4 may be elevated in contrast with decreased level of IFNγ in asthma. Determination of serum levels of IL-4 and IFNγ and correlations between them may be helpful for understanding the immunological mechanism in asthma.