Allergen specific immunotherapy (SIT) is the only treatment that can provide a cure for allergic disorders. This treatment is based on development of immune tolerance by exposure to allergen in repetitive and increasing doses. It is tertiary to avoidance of allergen and pharmacotherapy. Allergens used for immunotherapy, must be confirmed by skin prick test or specific IgE and must be applied in supervision of allergy specialists. Studies show that immunotherapy, improve asthma symptoms, decreases drug consumption, prevent development of asthma in rhinitis patients and reduce new sensitizations. Common side effects diminished with the usage of standardized allergen solutions. It is contraindicated in severe asthma. Though it is recommended to avoid immunotherapy in patients using beta blockers and ACE inhibitors, immunotherapy can be considered in mandatory situations regarding possible benefits and harms. Most common ways of administration are subcutaneous and sublingual; new methods such as epicutaneous and intralymphatic injections are currently being studied.