A pleural effusion resulting from pancreatitic-pleural fistula is a rare clinical entity which has, however, been more frequently recognised in the last ten years. The cause is a fistula tract between the pancreas and the pleura. Elevated amylase levels in the pleural fluid are the key to suspecting this diagnosis, which needs to be confirmed using imaging techniques such as CT, MRI and ultrasound or ERCP, which are necessary for defining the therapeutic strategy. After the failure of conservative management, a cysto-jejunostomy with a Roux-en-Y loop resolved the pleural effusion. This is the surgical technique of choice in the presence of a pseudocyst. We report details of a patient with a pancreaticopleural fistula diagnosed by ultrasonography, in which CT and ERCP were unable to demonstrate any communication between the pleural cavity and the pseudocyst. Only one similar case has been reported in the literature, diagnosed initially following visualization of a fistula tract at CT. We discuss the diagnostic and therapeutic options.