Antimicrobial peptides exhibit activity against bacteria, viruses, fungi, and parasites. They have been described not only as endogenous antibiotics but also as immune modulators with an impact on innate and adaptive immune functions. Asthma is one of the most common diseases, characterized by chronic airway inflammation, bronchial hyperreactivity and asthma attacks. Airway inflammation in asthma is characterized by allergic phenotypes, such as dense infiltration of eosinophils, mast cells, Th 2 lymphocytes and monocytes. Viral infections are often the cause of asthma exacerbation. This review highlights recent observations on the role of antimicrobial peptides in asthma pathogenesis.