Background: Allergic asthma is believed to be a T helper 2 cell (Th2) preponderant response caused by airway hyper-responsiveness. Interleukin-35 (IL-35) is a newly discovered anti-inflammatory cytokine. Objective: To determine whether the expression of IL-35 is associated with type-2 inflammation in children with asthma exacerbations. Methods: Thirty children (6-12 years old) with acute allergic asthma and twenty healthy controls were enrolled. Sputum was collected from lower airways. IL-35 and type 2 cytokines expression from serum and sputum were measured at mRNA and protein level by real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. The sampling and the test were repeated eight weeks after the asthma exacerbation. Results: At the time of exacerbation, IL-35 expression decreased significantly in induced sputum and serum than in the controls. The expression of IL-35 was negatively correlated with IL-4, IL-5 and IL-13 expression. The IL-35 from induced sputum increased significantly, whereas type-2 cytokines decreased significantly eight weeks after the exacerbation. Conclusion: Our results showed that decreased IL-35 was associated with type-2 cytokines in asthma exacerbations in children, suggesting that IL-35 may be a potential future drug target for asthma exacerbations.