Mannose-binding lectin (MBL) belongs to a family of glycoproteins called lectins or collectins, which possess many of the functional features of immunoglobulins. Mannose-binding lectin is a very important component of the innate immune system, which recognizes distinct pathogens and activates the classical path of the complement-fixation method. In humans, the serum levels of collectins vary widely, and their variability is correlated with susceptibility and resistance to infection and other diseases. Recent studys show that MBL gene polymorphism is involved in the pathogenesis of many diseases, including infectious and allergic illnesses. Our study aims to determine the role of MBL polymorphism in children diagnosed with allergic bronchial asthma, especially in acute episodes. We conclude that MBL2 gene polymorphism is associated with atopy, allergic diseases and acute respiratory tract infections with MBL deficiency in early childhood. In terms of genetic polymorphism, most of the studied alleles were type A, these being the most frequently present in the studied groups, while alleles B, C or D have been explored to a lesser extent. Studies are also required for adult patients with allergic and atopic conditions, because so far, most of the research has been done on pediatric population only.