BACKGROUND AND AIM: The aim of this study was to assess the incidence and etiology of acute pancreatitis at a major pediatric referral center in Australia. METHODS: A 10-year retrospective audit was conducted at The Royal Children's Hospital, Melbourne, Australia. All patients from 1993 and 2002 with a serum lipase level greater than three times the upper reference range and a history consistent with acute pancreatitis were included. RESULTS: During the 10-year period, 279 confirmed cases of acute pancreatitis were identified. The median age at presentation was 10 years (range, 0.2-15.9). In 209 (74.9%) patients, a likely cause of acute pancreatitis was found, including trauma (36.3%), systemic disease (22.2%), metabolic (5.8%), biliary (5.4%), drugs (3.2%), or viral illness (2.2%). In the remaining 70 (25.1%) cases, the pancreatitis was deemed idiopathic. Comparing data from 1993 to 1997 with data from 1998-2002, there was a significant increase in the annual incidence of pancreatitis (24.6 +/- 2.3 vs 31.2 +/- 6 cases per year; P = 0.04). A linear regression analysis showed a strong association between the incidence and the year of diagnosis (r(2) = 0.5775, P = 0.01). This increase was mainly due to a significant rise in idiopathic disease (r(2) = 0.83, P = 0.0002) and systemic disease (r(2) = 0.41, P = 0.048), whereas the incidence of other causes of acute pancreatitis remained unchanged. CONCLUSION: The incidence of acute pancreatitis in children has increased significantly over the past decade. The increase was greatest in children with idiopathic pancreatitis. It remains unclear whether this reflects a true incidence increase or improved clinical awareness.