Introduction: Despite significant progress in the treatment strategy of acute necrotizing pancreatitis (ANP), mortality in cases of its severe form remains high. There is no single point of view concerning the indications for the use of mini invasive interventions depending on the nature, extension and localization of the pathological foci of ANP. Material: We performed a prospective observational cohort study of efficacy of elaborated algorithmic mini invasive step-up approach of surgical treatment of 317 patients with different morphological forms of ANP. The following parameters were collected for each episode: length of hospital stay, mortality, occurrence of organ failure and local complications. Results: Transcutaneous punction/drainages were applied as the first step in 37 patients with acute necrotic collections (ANC). In the presence of walled-off pancreatic necrosis (WOPN) EUS procedures were preferred in case their close localization to the stomach or duodenum in 65 observations. Initial surgical treatment wasn't effective in 18.8% and video-assisted retroperitoneal debridement (VARD) in patients with ANC or necrosectomies under EUS control in cases of WOPN were applied. Necessary for laparotomic necrosectomies occurred in 14.5% of patients and was the final step of proposed algorithmic approach. During postoperative period complications occurred in 28.3% of patients. They included 7 new episodes of organ failure, 4 cases of arosive hemorrhage, and 5 observations of pancreatic and duodenal fistulas. Overall mortality rate was 3.3%, after interventional treatment - 6.5%. Conclusion: Surgical treatment in patients with ANP based on elaborated algorithmic step-up approach is followed by acceptable complication and mortality level.