We report the case of a VIPoma diagnosed in a 15-year-old teenager who experienced profuse secretory diarrhea associated with hypokalemia, metabolic acidosis and high plasma levels of vasoactive intestinal peptide (VIP) and pancreatic polypeptide (PP). Angiography showed an abnormal mass in the head of the pancreas. Before surgery, subcutaneous injections (100 micrograms every 8 hours) of the long-acting somatostatin analogue octreotide or SMS 201-995, were administered in order to stabilize the clinical status of the patient and to reduce the intravenous administration of fluid and electrolytes. This treatment resulted in prompt relief of the symptoms and in a partial decrease of the plasma levels of VIP and PP. At subsequent laparotomy, there was a tumour localized in the head of the pancreas, which was completely removed by Whipple resection. The immunohistochemical staining revealed the presence of VIP and PP inside the tumour cells. Two years after surgical resection, the patient is healthy without clinical or laboratory evidence of recurrence.