A child with a post-tramatic pancreatic pseuodocyst developed pancreatic fistula, following percutaneous drainage of the cyst. The fistula output was about 120ml/day and lasted for a month. A diagnostic ERCP revealed main pancreatic duct disruption. The fistula output ceased over the next two days following the ERCP. The patient has been well for the past four years. This patient's immediate recovery after ERCP could possibly be due to dislodgement of a mucus plug by the contrast injected during ERCP. Such a mechanism can explain the previous sporadic reports of spontaneous cure of persistent pancreatic fistulae in children.