Acute pancreatitis is a common and potentially fatal condition, with several well-known causes including gallstones, excessive alcohol consumption and specific medications. We report a case of an 89-year-old man presenting with acute pancreatitis, which we believe to be secondary to a diaphragmatic herniation of the pancreas. This extremely rare anatomical abnormality can be found incidentally in the asymptomatic patient or may present with a variety of acute symptoms. However, there have been only isolated reports of these cases presenting as acute pancreatitis. While the majority of acute pancreatitis cases can be explained by common causes, it is important that clinicians be aware of and should consider investigating for other more unusual possibilities, such as pancreatic herniation, before labelling an episode as ‘idiopathic’.