The diagnosis of acute pancreatitis is usually confirmed by a significant increase of the serum amylase and/or lipase level. However, serum pancreatic elastase?1 (pEla-1) was found to be a more sensitive diagnostic marker in acute pancreatitis (AP), when assayed by RIA procedure. We analysed the serum concentration of pancreatic elastase-1, measured by ELISA technique in 46 patients with acute pancreatitis and in the control group of 12 healthy volunteers. At admission (day 1) we found significantly higher pEla-1 level in patients with AP when compared to the control group. During the following days, the concentration of pEla-1 rapidly decreased nearly to undetectable value on the third day. There was no significant difference between patients with mild and severe AP and according to aetiology. We suggest that pEla-1 has a little diagnostic value and does not provide additional information to that of cheaper and more widely available serum amylase and lipase.