Fine-needle aspiration and endoscopic aspiration of pancreatic cells permit the diagnosis of pancreatic carcinoma and avoid the complications and morbidity of pancreatic biopsy. In this study, the accuracy of fine-needle and endoscopic aspiration were compared, and cytologic criteria for pancreatic carcinoma were sought. Pancreatic cytologic preparations from 79 patients, including 39 fine-needle aspirates and 48 endoscopic aspirates, were retrospective reviewed. When compared with definitive tissue diagnosis or clinical course, fine-needle aspiration had a sensitivity for pancreatic carcinoma of 79%. Endoscopic aspiration of pancreatic secretions had a sensitivity of only 33%. There was a single falsely suspicious fine-needle aspirate, but there were no false positive diagnoses when using either collection technic. Seventeen cytologic features were examined to determine cytologic criteria of malignancy. The presence of disoriented or crowded cells in three-dimensional groups, and extreme nuclear enlargement combined with nuclear contour irregularity were the best criteria for pancreatic malignancy.