To observe the distribution of multiple hormones in nonsecreting islet cell tumors of the pancreas and to study their histogenesis, 9 pancreas nonsecreting islet cell tumor cases were studies using 12 kinds of antisera. The results showed that 4 cases were positive for insulin, 6 for glucagon, 1 for gastrin, 6 for somatostatin, 1 for gastrin 5 for calcitonin, 7 for neurotensin, 4 for ACTH, 3 for TSH, 5 for FSH and 2 for LH. It is therefore confirmed that these tumors synthesize and secrete peptide hormones and glycoprotein hormones. We believe that these endocrine cells originate from primitive multipotential stem cells.