Four cases of endocrine tumors of the pancreas and, more generally, of the diffuse endocrine system, are presented here. Included are all the data relative to the inherited character of the disease covering two generations. Two brothers had Zollinger-Ellison syndrome--one of them probably, the other one proven (first case recorded in France). Both patient's only sons are currently treated for endocrine tumor of the pancreas and Zollinger-Ellison syndrome, respectively.