Objective: to analyze the generally accepted histological criteria for diagnosing the activity of inflammatory bowel disease (IBD) in patients with therapy-induced endoscopic remission. Subjects and methods. Colon biopsy specimens from 57 patients aged from 19 to 52 years (mean age 31±2.5 years), including 41 patients with ulcerative colitis (UC) and 16 with Crohn’s disease (CD) affecting the colon, were examined. All the patients had no clinical signs of disease activity; endoscopic examination diagnosed remission (none or minimal changes). The biopsy specimens were taken from all colon segments during colonoscopy and processed by conventional methods. Results. Persistence in chronic inflammation with signs of its activity (neutrophils in an infiltrate and cryptitis) and mucosal structural changes (no histological remission) were found in 29.3% of the patients with UC and 37.5% of those with CD (only in 31.6% of the patients). Persistence in chronic inflammation without signs of its activity and/or mucosal structural changes (incomplete histological remission) were detected in 80.5, 81.25, and 80.7% of the patients, respectively. Complete histological remission without mucosal inflammatory and structural changes was observed only in 19.5, 18.75, and 19.3% of the patients, respectively. Conclusion. The investigation shows that histological remission is still difficult to achieve to date, despite the use of the present-day treatment protocols for IBD. On the other hand, the conventional morphological criteria for the diagnosis of histological remission in IBD are quite subjective and need further discussion and agreement. Whether there may be a complete structural and functional recovery of the colon mucosa remains open.