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Background: Intraductal Papillary Mucinous Neoplasm (IPMN) is increasingly diagnosed due to the ubiquity of cross-sectional abdominal imaging and a growing awareness of the pathology. The treatment algorithm for IPMN remains controversial and depends heavily on the malignant potential of the disease and anticipated outcomes.Methods: We evaluated all patients who underwent surgical resection for IPMN between January 1997 and December 2009. Adenomas and moderately dysplastic lesions were classified as benign. High grade dysplastic lesions, carcinoma in situ (CIS), and invasive cancer were considered malignant. Pathology reports were retrospectively reviewed to distinguish main-duct, mixed, and branch-duct types. Continuous variables were compared using Student’s t test and categorical variables were compared using Fisher’s exact tests. Results: Between 1997 and 2009, 146 patients underwent surgical resection for IPMN. During this period 88 patients were surveyed for suspected IPMN, and 278 underwent pancreatectomy for other cystic neoplasms. The majority of patients with IPMN presented as an incidental finding (42.6%), followed by abdominal pain (19%) and pancreatitis (17%). Patients with benign disease were on average younger than those with malignant disease (66.4 vs. 70.6 years, p=0.01). The majority were female (54%) and white (86.2%). Most resections were partial pancreatectomies (82%), but 27 patients required a total pancreatectomy. Main-duct type was identified in 33%, branch-duct type in 23%, and mixed-type in 39% of patients. Of the main-duct and mixed lesions, 39% harbored malignancy, 50% of which were invasive carcinomas. Eight (24%) branch-duct lesions were high-grade dysplastic or CIS, but none were invasive carcinomas. The overall rate of malignancy for IPMN patients was 35%. IPMN was identified on the final surgical margin in 25% of patients. Five patients have undergone completion pancreatectomy at an average of 17.8 months after their initial surgery (range 8.7-27.5). Lesions requiring reoperation were either main-duct or mixed and tended to be malignant (p=0.05). None of these patients had IPMN at the original surgical margin. Three additional patients have recurred, two with locally advanced disease. Conclusions: Our series confirms a low rate of malignancy in branch-duct pathology and supports the judicious surveillance of these patients. Risk of recurrence necessitates continued surveillance after surgery. Patients with malignancy were older, suggesting a four year lag-time between adenoma and invasive disease.