OBJECTIVE To ascertain the best management options for patients presenting with gallbladder polyps. DESIGN Retrospective case-note analysis. SETTING Tertiary referral teaching hospital practice. PATIENTS Patients with ultrasonography-detected gallbladder polyps. INTERVENTIONS Ultrasonography surveillance or surgery. MAIN OUTCOME MEASURES Demographic data and size and number of polyps were recorded as well as size increase and histological findings. Detection rates for potentially neoplastic and frankly neoplastic polyps were recorded and compared with complication rates from cholecystectomy. Cost-effectiveness of ultrasonography surveillance was examined. RESULTS Nine hundred eighty-six patients were identified and 467 patients underwent further follow-up. Only 6.6% of polyps exhibited an increase in size over the surveillance period. Polyps that subsequently progressed in size on surveillance had a significantly greater diameter at first presentation than those polyps that remained static (7 mm vs 5 mm, respectively) (P < .05). Only 3.7% of resected polyps had malignant or potentially malignant histology. Size greater than 10 mm and increase in size during surveillance predicted neoplastic potential. CONCLUSIONS A surveillance with or without selective surgery policy could potentially detect and prevent 5.4 gallbladder cancers per 1000 individuals per year with a cost saving of more than £130 000 (US $201 676) per year. Cancer prevention benefits would exceed the risk ratios from cholecystectomy complications. Polyps greater than 10 mm should be resected; those between 5 and 10 mm should be under ultrasonography surveillance.