Serous cystadenoma of the pancreas is a rare lesion thought to be almost invariably benign. Since 1978, 211 cases have been reported in the literature. Some have been recognized by computed tomography (CT) when small and asymptomatic. The authors have reviewed their experience with 40 patients (median follow-up of 1.9 years, maximum of 22.2 years) from 1936 to 1991. One third (13) were asymptomatic, of whom eight (20%) were discovered intraoperatively. Of those 20 who had CT, an unequivocal preoperative diagnosis was reached in none. Needle biopsy proved accurate in two patients. Endoscopic retrograde cholangiopancreatography (ERCP) and biopsy were performed with diagnostic success on one occasion. Three patients presented acutely. The tumor was resected in 90%, with an operative mortality rate of 10%. Enucleation of the tumor without formal anatomic pancreatectomy necessitated reoperation for complications in four of eight patients. Survival after successful resection paralleled expected survival. Serous cystadenoma may be associated with von Hippel-Lindau syndrome. The current role for conservative management remains questionable because of our current inability to reliably differentiate many of these benign neoplasms from malignant cystic neoplasms of the pancreas.