OBJECTIVE: Interferon-gamma (IFN-γ) and interleukin-4 (IL-4)are typical cytokines produced by CD4~+T cells under antigenic stimulations, and the changes of serum levels of the two cytokines can indirectly reflect the immune state and the progress of inflammation. The aim of this study was to investigate the changes of IFN-γ and IL-4 in peripheral blood of children with Mycoplasmal pneumonia. METHODS: The peripheral blood concentrations of IFN-γ and IL-4 were measured using ELISA in 40 children with Mycoplasmal pneumonia at the acute stage. The samples from 40 healthy children were used as the Control group. RESULTS: The serum concentrations of IFN-γ and IL-4 in the Mycoplasmal pneumonia group were 99.43±13.18 and 44.61±17.46 pg/mL, respectively, which were higher than those in the Control group (86.23±6.31 and 25.97±9.40 pg/mL respectively; P<0.05). CONCLUSIONS: There was an imbalance in cytokine secretion in children with Mycoplasmal pneumonia at the acute phase, suggesting that adjuvant immunological therapy is needed for Mycoplasmal pneumonia.