It has been supposed that there are differences with regard to clinical course and outcome due to the underlying etiological factor in acute pancreatitis. Therefore, the objective of this study was to analyze the severity of the disease, serum enzymes, indicators of necrosis, systemic complications, and mortality in acute pancreatitis with regard to the etiology. One hundred ninety patients with acute pancreatitis (127 male, 63 female) were studied prospectively and subdivided into three etiological groups: (i) alcohol, (ii) gallstones, and (iii) other causes and idiopathic acute pancreatitis. Severity scores (Ranson and Bank) and findings by contrast-enhanced computed tomography were similar in all three groups. Analysis of serum enzymes [lipase, aspartate aminotransferase (ASAT)] and indicators of necrosis (C-reactive protein, alpha 1-antitrypsin, alpha 2-macroglobulin, and lactate dehydrogenase) showed only for ASAT within 24 h significantly higher levels in biliary acute pancreatitis in comparison with the other groups. There were no differences in the rate of infected pancreatic necrosis and mortality in alcohol-related acute pancreatitis (31 and 5.3%), biliary acute pancreatitis (38 and 10%) and acute pancreatitis due to other etiological factors (43 and 5.5%). In conclusion, this study clearly showed that once the pathogenetic mechanisms have initiated the disease, the course and outcome of acute pancreatitis are not influenced by the underlying etiological factor.