Aim. To retrospectively evaluate the efficiency of long-term infliximab (INF) therapy in patients with refractory ulcerative colitis (UC). Subjects and methods. The investigation enrolled 48 patients with refractory UC who had taken IFL in 2008 to 2014. Steroid-dependent or steroid-refractory UC was established in 40 (83.3%) patients; 8 (16.7%) were noted to be refractory to therapy with azathioprine or 6-mercaptopurine. Cytomegalovirus DNA was identified in the biopsy specimens of the large intestinal mucosa (LIM) from 7 patients. One patient received antiviral therapy. Induction therapy with IFL was in its administration in a dose of 5 mg/kg at 0, 2, and 6 weeks, then maintenance therapy was continued every 8 weeks. Results. After an IFL induction cycle, 3 (6.3%) patients were unresponsive to therapy and were excluded from the investigation. At present, 25 (55.5%) of the 45 patients who have responded to the therapy continue to take IFL 5 mg/kg every 8 weeks and are in clinical remission; 4 (8.8%) patients receive intensified IFL therapy. Initially 23 patients received combined therapy with IFL + an immunosuppressive drug; 22 had IFL monotherapy. Escape from the effect of the performed therapy was observed in 5 (11.1%) patients, which required its intensification. The intensified therapy resulted in sustained remission in 4 (8.8%) patients; colectomy was carried out in one (2.2%) case. Secondary loss of response to IFL, its intolerance, development of severe infectious complications, which did not allow for further maintenance therapy with IFL, were seen in 11 (24.4%) patients; 5 (11.1%) stopped the therapy because they had been excluded from the additional drug subsidy list. Maintenance therapy with IFL proved successful during 64 months in 29 (64.4%) of the 45 patients and during 64 months if its intensity, when the occasion required, was enhanced. Conclusion. The long-term use of IFL in UC confirmed its high efficacy in achieving clinical response, in inducing a clinical remission and its capacity to heal LIM, and in sustaining remission.