Aim. Analysis of the results of the application of the modified step-up approach in the treatment of infected pancreatonecrosis in a third-level hospital.Materials and methods. The study included 52 patients over 18 years of age with acute pancreatitis and suspected or proven infection with pancreatic or peripancreatic necrosis .The control group included 27 patients who underwent primary open necrectomy. The comparison group included 25 patients who underwent surgical treatment within the framework of the modified concept of the stepwise surgical approach (Step-up). In the groups compared mortality rates, early postoperative complications (IIIb-IVb grade Clavien-Dindo), late postoperative complications (ventral hernias, pseudocysts, diabetes mellitus), the duration of inpatient treatment, and the duration of treatment in the intensive care unit. The indicator "Full return to primary social activity after treatment" was also proposed.Results. In the Step-up approach group, in comparison with the control group, there was a decrease in the overall incidence of postoperative complications of IIIb-IVb grade Clavien-Dindo (24% and 51.9%, respectively, p <0.05), the frequency of arrosive bleeding (0% and 14 , 8%,  respectively, p <0.05), the need for necrsequestrectomy (64 and 100%, respectively, p <0.01), the total average duration of treatment in the intensive care unit (3.2 ± 0.6 and 9.2 ± 1.6 days, respectively, p <0.05), and the average duration of treatment in the intensive care unit after execution of necrosectomy (1,4±0,4 7,2±1,3 days, respectively, p<0.01).  A complete return to social activity in the control group was noted only in 10 (37%) patients compared with 19 (76%) in the Step-up group (p <0.01).  In the Step-up group, in comparison with the control group, a tendency towards a decrease in mortality was revealed (16% and 34.5%, respectively, p> 0.05).Conclusion. The step-up approach can improve the results of treatment of infected pancreatic necrosis. The most important advantage of this concept is reproducibility - that is, the possibility of using it not only in the leading metropolitan clinics, but also in the regions of the Russian Federation. The step-up approach, however, has not yet acquired a complete form, and there is room for improvement.