The aim of the study which included 2311 patients (aged 18—80 yrs), examined by 100 physicians (57% allergists, 37% pulmonologists and 7% general practitioner) in 18 Russian cities, was to assess the prevalence of allergic rhinitis in patients with asthma, as well as to evaluate the specifics of the course of these diseases, when concomitant or not. The study design included one outpatient visit, followed by the completion of studyspecific case report forms and Asthma Control Questionnaire (ACQ) validated for use in Russia. The vast majority (88%)of asthma patients had concomitant allergic rhinitis (Group 1). Patients with asthma only (Group 2) were older (50,6±0,78 vs 41,9±0,35 yr, p<0,05, had more severe asthma course (FEV t 70,6±1,1 vs 78,3±0,46% of predicted, p<0,05), lower prevalence of atopy (45% vs 98%, p<0,05) , higher body mass index (BMI) (28,2±0,27 vs 27,3±0,12, p<0,05), and smoked more often compared to Group 1 (30% vs 23%, p<0,05). The treatment of concomitant allergic rhinitis recommended in current clinical guidelines may improve asthma control. Significant proportions of patient with asthma (27%) and allergic rhinitis (41%) were treated not in line with evidence-based International and National Guidelines. The conclusion of this study is that allergic rhinitis is a common comorbidity in patients with asthma. The implementation of the evidence based approach to diagnosis and treatment of both diseases, in accordance with current clinical guidelines, in real clinical practice in Russia is extremely important.