The female patient in this report was suffering from a pancreatic islet cell tumor which exhibited ectopic ACTH syndrome associated with Zollinger-Ellison syndrome. When this combined syndrome was diagnosed, there were already multiple metastasis to the liver. Zollinger-Ellison syndrome was treated with a histamine-H₂-receptor blocker, and ectopic ACTH syndrome was controlled with trilostane, metyrapone and o, p'-DDD. She survived more than 6years after the diagnosis, mostly as an outpatient. During treatment she became cachexic. After she died, an autopsy was done. Immunohistochemical staining established that tumor cells contained ACTH- and gastrin-like immunoreactivity. Our treatment suggested the efficacy of chemical adrenalectomy in managing ectopic ACTH syndrome associated with Zollinger-Ellison syndrome.