Cytological verification of the angiographic, sonographic, and/or intraoperative diagnosis of pancreatic or ampullary carcinoma may be achieved by fine-needle aspiration biopsy (FNAB). Fifteen biopsies were done in 13 patients, 12 of whom were thought to have pancreatic carcinoma clinically. The FNAB specimen confirmed this in 11 of them. Also, one equivocal (suspicious), two false-negative, and no false-positive results were recorded. Complications were not seen. In addition, four patients with ampullary carcinoma had pancreatoduodenectomy on the basis of FNAB specimens. Since this method is more accurate and is safer and simpler than the traditional wedge or core biopsy of suspected pancreatic or ampullary tumors, and since it may eliminate the need for laparotomy in selected cases, we consider it the preferred method for immediate diagnosis of these neoplasms.