Allergen-specific immunotherapy (ASIT) is the only pathogenic treatment for IgE-mediated pollen diseases (allergic rhinitis and allergic conjunctivitis), as well as atopic asthma and hypersensitivity to Hymenoptera venom. There are two forms of ASIT: subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT). Despite the 25-year-old experience of application SLIT, presently there remain doubts about the comparability of these methods in their efficacy and safety. Objective. To comparatively analyze the efficiency and safety of SCIT and SLIT. Patients and methods. The investigation enrolled 60 patients aged 18 years and older with confirmed sensitization to tree pollens and clinical symptoms of allergic rhinitis and allergic conjunctivitis. All the patients were randomized into two groups of 30 people each: Group 1 received SCIT and Group 2 had SLIT. Fostal—tree pollen allergen and Staloral—birch pollen allergen were used for SCIT and SLIT, respectively. The Rhinoconjunctivitis Quality of Life Questionnaire was applied to identify the efficiency of ASIT. Results. SCIT and SLIT were shown to have a statistically confirmed positive impact on the overall index of quality of life as a whole and its individual indicators. After SCIT and SLIT, a comparison revealed no significant intergroup differences in the total indicators of their impact on various spheres of life. Conclusion. ASIT as a current effective and safe treatment for pollinosis makes it possible not only to modify the course of the disease, by reducing its activity and the need for drugs, but also to achieve a long-term positive effect that persists after therapy termination and to improve quality of life in patients with allergic rhinitis and allergic conjunctivitis.