Seven patients with clinical features of the glucagonoma syndrome, including the characteristic rash, diabetes mellitus, and weight loss, were examined by CT. Computed tomography demonstrated a primary pancreatic tumor in all patients, and, in four, hepatic metastases were identified. The primary tumors, relatively large and solid in nature, varied in size from 2.5 to 6 cm in maximum diameter. The tumor was found in the tail of the pancreas in three patients and in the head of the pancreas in four. No obliteration of adjacent perivascular or peripancreatic fat planes was observed in any patient. Calcification was present in the primary tumor in three patients and in the hepatic metastases in one. All tumors that were studied angiographically were found to be hypervascular. In contrast to insulinomas, which are frequently quite small when clinically diagnosed, glucagonomas appear to attain considerable size prior to being clinically apparent. Thus, we conclude that CT ought to become the mainstay in the identification, localization, and staging of these tumors. © 1985 Raven Press.