This article examines the choice of hospital for elective hip replacements amongst patients in England, using patient-episode level data from the Hospital Episodes Statistics records. The article is primarily methodological: we estimate a demand model that allows for heterogeneity across observed patient characteristics and demonstrate how to use this model to simulate the effect of mergers between hospitals. Our article contributes to the empirical literature on hospital choice and provides a novel method for simulating mergers between hospitals with regulated prices. Importantly, in an industry that competes on quality, our demand model estimations also identify important quality dimensions of choice.