Aim. To define the prognostic factors for puncture drain interventions efficiency and of an optimal time point for the open surgeries. Methods. Surgical treatment results in 56 patients with acute pancreatic necrosis are described. The first group (28 patients) included the patients treated only by. The second group (28 patients) included the patients who underwent puncture drain interventions with further open surgery. Puncture drain surgery efficiency was evaluated using laboratory data and results of instrumental examinations. Results. Body temperature, leukocytosis and a «left shift» on a white blood cell count performed not later than 7 days after the surgery were the key factors for assessing the puncture drain surgery efficiency. During the first 7 days after surgery the body temperature has come to normal in 100% of patients from the first group and in 30% of patients from the second group (c2=15,83, р 0,0005), in other 70% of patients from the second group the body temperature has come to normal later than 7 days after surgery. White blood cell count has come to normal during the first 7 days after surgery in 75% of patients from the first group and in 0% of patients from the second group (c2=11,14, р 0,0016), in 25% of patients from the first group and in all patients from the second group it has only came to normal range at least 7 days after surgery. A marked «left shift» during the first 7 days after surgery was registered in 50% of patients from the first group and in 0% of patients from the second group (c2=6,12, р 0,05), in 50% of patients from the first group and in all patients from the second group it has only came to normal range at least 7 days after surgery. A conservative approach should be preferred if these parameters improve over time and no significant changes in pancreas are seen on computed tomography, otherwise, especially when there are the signs of incomplete debridement on the computed tomography, an open-access surgery should be performed. Conclusions. Puncture drain intervention may be an independent and final method of surgical treatment or may become the first stage of combined surgical treatment in patients with acute pancreatic necrosis. Indications for an open-access surgery should be assessed 7-8 days after the puncture drain surgery was performed if no positive change of laboratory data is seen.