The purpose of the study is to investigate the course of acute pancreatitis in obese patients, the development of local and systemic complications and mortality rates.We took and analyzed 482 histories of acute pancreatitis treated at Kyiv Regional Clinical Hospital from January 1, 2011 to February 2, 2019. The data were statistically processed in the Excel 2010 program using a descriptive method applying relative, absolute numbers, mean square deviations and their errors. A correlation between variables was studied using the Pearson's test (R2). The significance of the difference between the two independent groups was tested with Student's t-test.We included 482 patients in our study, i.e. 260 patients (54%) with obesity (the study group), and for comparison, 222 (46%) patients with normal body mass, constituting a control group. Obese patients had a higher mean age (55.4 ± 9.4 years, P = 0.01); also, they showed a statistically higher incidence of severe course of acute pancreatitis [85 (32.7%) vs. 16 (7.2%); P = 0.01*]. We noted an increase in the rate of acute pancreatitis with severe course in obese patients with mass gain (from 10.20% to 53.93%, P = 0.03*). Hospitalization time of obese patients was longer than in case of patients with normal body mass. In addition, we observed a two-fold longer hospitalization of obese patients at intensive care units (5.8 ± 0.8 vs. 2.7 ± 0.5 days, P = 0.01*). When investigating the mortality rate, we found out that the main cause of death was the progression of organ failure - 30 cases (6.3%), pulmonary embolism (TB) - 15 (3.1%) and DIC - 18 (3.7%). C onclusions: The presence of obesity in patients involves a high risk of severe acute pancreatitis. This risk increases with body mass increase. In addition, in obese patients the hospitalization and in-patient care takes longer, which increases the total cost of treatment and requires a cost-effective algorithm in the future. A high mortality rate in obese patients requires an improved treatment algorithm.