Background. The problem of comorbidity is becoming increasingly important in modern medicine and healthcare. A combination of infl ammatory bowel diseases (IBD) and spondyloarthritis (SpA), the genesis of which is closely related to immune infl ammation, can be attributed to the number of comorbid mutually aggravating pathology. In real clinical practice, there is often a late diagnosis of these comorbid processes, which aff ects the quality and eff ectiveness of treatment and worsens the outcomes of diseases.Aim. In order to attract the attention of specialists of various profi les to immuno-i nfl ammatory comorbidity, the article presents current data on the association between IBD and SpA with an analysis of the frequency of joint and spine lesions in ulcerative colitis (UC) and Crohn’s disease (CD), as well as the frequency of detection of intestinal lesions in various SpA phenotypes.Basic provisions. It has been shown that joint lesions in IBD and intestinal lesions in SpA, as a rule, occur in severe and moderate forms of these diseases, occurring with high or moderate activity. The HLA B27 genotype is more typical for individuals with manifest SpA, including developed against the background of IBD. The combination of IBD and SpA is caused by similar disorders of immunoregulation, the functional state of cells of native and adaptive immunity, and an imbalance of cytokines. These mechanisms have become the basis for the use of biological and targeted therapy in IBD and SpA, as well as in their combination. It has been shown that approximately half of patients resistant to standard drugs can achieve clinical remission on biological therapy.Conclusions. Thus, in order to objectify the severity of the immuno- infl ammatory process and improve outcomes, it is advisable to diagnose the most likely comorbid pathology in a timely manner and take this factor into account to optimize treatment.