BACKGROUND:: A recent systematic review found early laparoscopic cholecystectomy (ELC) to be safe and to shorten total hospital stay compared with delayed laparoscopic cholecystectomy (DLC) for acute cholecystitis. The cost-effectiveness of ELC versus DLC for acute cholecystitis is unknown. METHODS:: A decision tree model estimating and comparing costs to the UK National Health Service (NHS) and quality-adjusted life years (QALYs) gained following a policy of either ELC or DLC was developed with a time horizon of 1 year. Uncertainty was investigated with probabilistic sensitivity analysis, and value-of-information analysis estimated the likely return from further investment in research in this area. RESULTS:: ELC is less costly (approximately - pound820 per patient) and results in better quality of life (+0.05 QALYs per patient) than DLC. Given a willingness-to-pay threshold of pound20 000 per QALY gained, there is a 70.9 per cent probability that ELC is cost effective compared with DLC. Full implementation of ELC could save the NHS pound8.5 million per annum. CONCLUSION:: The results of this decision analytic modelling study suggest that on average ELC is less expensive and results in better quality of life than DLC. Future research should focus on quality-of-life measures alone. Copyright (c) 2009 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.