The paper describes the authors' personal experience of internal pancreatic fistulas. This is an uncommon pathology which should however be taken into account in the presence of ascites or pleural effusion without a clear cause. Essential diagnostic tests are chemical and physical examination and the assay of amylase in ascitic or pleural fluids. Medical treatment is sometimes efficient leading to the disappearance of the fistula. If medical therapy fails, surgery is necessary, based on pancreatic resection or the drainage of the cyst or interrupted pancreatic duct.