BACKGROUND Acute pancreatitis, a sudden inflammation of the pancreas, can result in severe complications. The presence and volume of ascites, an abnormal accumulation of fluid in the abdomen, has been linked to disease severity. Our study investigates ascites volume, quantified via abdominal CT scans, as a potential predictive tool for disease severity. MATERIAL AND METHODS In this retrospective analysis, patients diagnosed with acute pancreatitis were evaluated. Patients were categorized into groups with and without ascites, with comparisons made regarding clinical characteristics. We further compared the mean ascitic volume against various outcome parameters in patients with ascites. Ascites volume and other predictive systems were assessed through receiver operating characteristic (ROC) curves, with the area under the ROC curve (AUC) for different predictive systems being analyzed. RESULTS The ascites group had higher severity scores and related serological indexes (P<0.05 for all). Among patients with ascites, a significant correlation was observed between ascites volume and outcome parameters (P<0.05 for all). The area under the ROC curve for predicting severe acute pancreatitis was 0.896, with 93% sensitivity and 79% specificity. Ascites volume yielded the highest diagnostic odds ratio (53.1; 95% confidence interval: 13.2,199.6). CONCLUSIONS Early-stage acute pancreatitis patients with ascites are indicative of severe illness and poor prognosis. An increase in ascites volume correlates with adverse clinical outcomes, thus highlighting the significance of ascites volume as a prognostic marker. This underscores the importance of abdominal CT in measuring ascites volume to predict disease severity.