Adenocarcinomas of the pancreas were experimentally induced in rats after the implantation of 7,12-dimethylbenz[alpha]anthracene (DMBA). Rats were anesthetized with Nembutal, the pancreas was exposed, and a 2- to 3-mm incision was made in the "head" of the pancreas approximately 1 cm from the duodenum. Crystalline DMBA (2-3 mg) was implanted and the incision was closed with silk suture. Eight % of animals developed tumors in the pancreas from 119 to 363 days after implantation (mean, 194 days). Ten animals developed tumors in less than 180 days. The adenocarcinomas were invasive, metastasized, and had pronounced ductal cell characteristics. The light-microscopic morphology of these pancreatic tumors was presented.