The allergen specific immunotherapy is the only valuable method to modify a natural course of disease in the treatment of allergic rhinitis. This has been used for the treatment of allergic diseases such as rhinitis and asthma since the beginning of the 20th century. Many different methods have been developed and are being developing in the immunotherapy field. But classical allergen specific injection immunotherapy is still the most widely used one in the world. And the mechanism of this therapy has been revealed by a lot of research, which has been concluded to modify the T cell response to allergen exposure. It generally is indicated for patients who have a clinically relevant IgE-mediated disease, especially in whom environmental control and pharmacotherapy inadequately treat the symptoms. Recently, the indications of immunotherapy are getting wider. The efficacy and duration is not standardized yet. And newly discovered antigen and alteration of allergen should be considered as important factors to evaluate the patients and initiate the immunotherapy. The development of standardization of extract and well-organized schedules of injection reduce the risk of complications of immunotherapy. The scope of this review is to highlight the recent information and practical approach of the allergen specific injection immunotherapy.