Undiagnosed masses in the pancreas represent a problem at laparotomy. Intraoperative biopsy of pancreatic lesions frequently fails to detect carcinoma and may cause severe complications. The aim of the present study was to determine the diagnostic accuracy of intraoperative fine needle aspiration cytology (FNAC) of pancreatic lesions. Ninety patients were studied from January 1988 to June 1992. The cytologic diagnoses were correlated with histology, autopsy results or clinical follow-up. Aspirates were reported as benign, suspicious, malignant or unsatisfactory. Final diagnosis of malignant pancreatic disease (MPD) was established in 60 patients and of benign pancreatic disease in 30. Among the 60 cases with MPD, the cytologic diagnosis was concordant in 42 and interpreted as suspicious in 4. Seven patients with benign cytology and 7 with unsatisfactory cytology later proved to have malignant disease. A total of 30 patients had benign disease; 26 of them had benign cytology. The remaining four had "unsatisfactory" cytologic reports. No false positives were reported. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy for intraoperative FNAC results were 80%, 100%, 100%, 70% and 91%, respectively. No complications followed the procedure. Intraoperative FNA of the pancreas is a safe and highly accurate diagnostic method for pancreatic lesions at laparotomy.