Objective: In this study, it was aimed to investigate the percentage of immature granulocytes (IG) and other hemogram parameters in the early period in predicting severe disease, in-hospital and short-term mortality in patients with acute pancreatitis (AP). Materials and Methods:Our study was designed as a retrospective observational clinical study. Patients admitted to the emergency department with the diagnosis of AP between 01.01.2017 and 31.12.2021 years were included in the study. Hemogram parameters were compared according to mortality and the Balthazar severity index. Results:We found that the percentage of IG was not statistically significant for mortality and disease severity. We found that the mean age of the group with mortality was statistically significantly higher than that of the group without mortality (p=0.012). We found that the lymphocyte count was statistically significantly lower in the group with mortality compared to the group without mortality. When we grouped the patients according to the Balthazar severity index, 366 (85.12%) of the patients were evaluated in the mild group, 61 (14.19%) in the moderate group, and 3 (0.69%) in the severe group. Among the groups; we found significant differences in hemoglobin, white blood cell (WBC), neutrophil, length of stay, and Balthazar severity index. Conclusion:The IG percentage does not have a predictive value for the severity of the disease and the mortality process, particularly in patients with mild AP. A decrease in lymphocyte count can be considered a marker for mortality and long-term hospitalization. In patients with AP, WBC count and neutrophil count can be used to predict the severity of the disease on the first admission to the emergency department.