Clinical studies suggest that pancreatic cancer occurs more often in persons with diabetes mellitus [1-7]. We have previously shown that the hamster pancreatic carcinoma cell line H2T grows more rapidly when implanted in streptozotocin (STZ)-diabetic hamsters [8]. To determine if enhanced growth of pancreatic carcinoma cells in diabetic hamsters is due to polyphagia associated with diabetes, H2T cells were implanted into the cheek pouch of three groups of animals: normal hamsters (group I), STZ-diabetic hamsters (group II), and STZ-diabetics pairfed to normals (group III). Tumor weights 30 days after implantation were 172 g in group I, 368 g in group II, and 369 g in group III (P less than 0.007). There was no significant difference between the two diabetic groups. Thus, STZ diabetes appears to promote the growth of pancreatic carcinoma cells by a mechanism other than increased nutrient intake by diabetic tumor hosts.