Background. Inflammatory bowel diseases (ulcerative colitis and Crohn’s disease) are serious problem in modern gastroenterology, as these diseases affect the working population, have a progressive chronic course, a high risk of disabling complications and require significant costs for the drug management.Aim. We wanted to assess the inflammatory bowel diseases structure and features of the use of basic drugs in outpatient and inpatient treatment in St. Petersburg, Russia.Materials and methods. A cross-sectional study was performed. Data about drug therapy, disease features and demographic from 42 outpatient institutions and from 6 city hospitals for the period 2018–2020 in St. Petersburg was collected. The analysis included data from 617 patients with ulcerative colitis and 455 patients with Crohn’s disease.Results. The median age of patients with ulcerative colitis was 44 years, which was statistically significant more than with Crohn’s disease (39 years). In ulcerative colitis, the left-sided localization of colon lesions (56%) prevailed over total colitis (23%) and proctitis (21%) In Crohn’s disease, the prevalence of ilecocolitis (36%) was approximately equal to the prevalence of colitis (35%), the frequency of terminal ileitis was significantly less (26%), other variants of gastrointestinal lesions were found in 3% cases. In Crohn’s disease compared to ulcerative colitis, the proportion of patients with mild disease was similar (36.6% and 38.2% respectively), but in in Crohn’s disease the frequency of severe disease there was more than three times compared to ulcerative colitis. There has been a significantly higher incidence of surgery in the past for Crohn’s disease compared to ulcerative colitis (14.8% and 2.6%, respectively). The vast majority of patients (more than 80%) received therapy with oral 5-aminosalycilic acid drugs. Topical formulas of 5-aminosalycilic acid drugs in ulcerative colitis were prescribed in about 50% of cases (it was significantly less than commonly used in Crohn’s disease). Corticosteroids were used in the treatment of 16.6% of ulcerative colitis patients and in 24.4% Crohn’s disease patients. In both diseases in the conditions of inpatient treatment, this group of drugs was used several times more often than in outpatient observation. Immunosuppressants (tyopurines, methotrexate) were administered in 6.9% ulcerative colitis patients with and in 17.0% Crohn’s disease patients.Conclusion. Clinical features of inflammatory bowel diseases in St. Petersburg and the features of basic therapy in comparison with the nationwide indicators in Russia demonstrate similar trends. The key problem points of therapy of inflammatory bowel diseases remains the widespread use of drugs of the group of 5-aminosalycilic acid in Crohn’s disease, insufficient use of rectal forms of 5-aminosalycilic acid in ulcerative colitis, a relatively small frequency of use of immunosupressors to maintain remission in Crohn’s disease. The solution to the problem of optimizing the therapy of patients with inflammatory bowel diseases within the framework of routine practice includes educational activities, as well as the creation of a regional register of patients with inflammatory bowel diseases in St. Petersburg.