Intraductal papillary mucinous tumors of the pancreas are rare and characterised by a malignant potential. Their natural history is unknown. We report a case of intraductal papillary mucinous tumor of the pancreas, that was still benign although the first symptom was appeared 30 years before the diagnosis. This case report demonstrate the possible slow course of these tumors, for which malignant degeneration is unpredictable.