OBJECTIVE: To assess the cost-effectiveness of bivalirudin versus heparin and glycoprotein IIb/IIIa inhibitor (H-GPI) in patients undergoing primary percutaneous coronary intervention (PPCI) for acute ST-segment elevation myocardial infarction (STEMI), from a UK health service perspective. DESIGN: Cost-utility analysis with life-long time horizon. MAIN OUTCOME MEASURES: Costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness. METHODS: Event risks and medical resource use data derived from the HORIZONS-AMI trial were entered into a decision analytic model. Clinical events until the end of year 1 (main model) or year 3 (alternative model) were modelled in detail. Adjustments were applied to approximate UK routine practice characteristics. Life expectancy of 1-year or 3-year survivors, health-state utilities, initial hospitalisation length of stay in the comparator strategy and unit costs were based on UK sources. Costs and effects were discounted at 3.5%. RESULTS: The main model predicted bivalirudin and H-GPI patients to survive 11.52 and 11.35 (undiscounted) years on average, respectively, and to accrue 6.26 and 6.17 QALYs. Patient lifetime costs were £267 lower in the bivalirudin strategy (£12 843 vs £13 110). Extensive sensitivity and scenario analyses confirmed these results to be robust. In probabilistic analysis, quality-adjusted survival was higher and costs were lower with bivalirudin in 95.0% of simulation runs. In 99.2%, cost-effectiveness was better than £20 000 per QALY gained. Results from the alternative model were fully consistent. CONCLUSION: The use of bivalirudin instead of H-GPI in STEMI patients undergoing PPCI is cost-effective, and offers a high probability of dominance. Background treatment with aspirin and clopidogrel is assumed.