The pathogenetic aspect of allergic bronchial asthma is characterized by airway inflammation with infiltration of mast cells, basophils, eosinophils, monocytes and T-helper (Th)2 lymphocytes. Most cases of asthma are atopic in nature and aeroallergens such as those released by pollens, Dermatophagoides, moulds etc, act as sensitizer and trigger agents which induce immune response through immunoglobulin E (IgE). IgE is the key mediator of allergic inflammatory reaction and plays a central role in the pathogenesis of atopic-allergic diseases such as those of respiratory tract: rhinitis and bronchial asthma. Currently antiinflammatory and bronchodilation treatments, with integration of other drugs such as antileucotrienes, are effective for most of asthma patients, but there are asthmatic subjects whose disease is incompletely controlled by inhaled or systemic corticosteroids and these patients account for about 50% of the healthcare costs of asthma. A novel therapeutic approach to asthma and other allergic respiratory diseases involves interference in the action of IgE and IgE has been viewed as a target for novel immunological drug development in asthma. Monoclonal antibodies are a molecule able to interact with specific antigens and represent a very interesting options for asthma treatment and their patents. Omalizumab is a humanized recombinant monoclonal anti-IgE antibody developed for the treatment of allergic diseases and with clear efficacy in adolescent and adult patients with moderate-to-severe allergic asthma. This non-anaphylactogen anti-IgE antibody inhibits IgE functions blocking free serum IgE and inhibiting their binding to cellular receptors. By reducing serum IgE levels and IgE receptor expression on inflammatory cells in the context of allergic cascade. Omalizumab therapy is well tolerated and significantly improves symptoms, reducing asthma exacerbations and the need to use high dosage of inhaled corticosteroids to control disease. Moreover, omalizumab improves quality of life of patients with severe persistent allergic asthma that is inadequately controlled by currently available asthma medications. In conclusion omalizumab represents a really new approach to the treatment of atopic asthma and may fulfil an important need in patients with moderate-to-severe asthma.