Objective: To explore variation in practice and its impact on QoL in management of acute coronary syndromes (ACS), the commonest cardiac cause of hospital admission. Methods: A prospective, international, observational study recruited ACS patients undergoing percutaneous coronary intervention (PCI), January - August 2007, capturing practice patterns, resource use and QoL. Results: A total of 1525 ACS-PCI patients (Spain-538, UK-504, France-483), under 122 cardiologists, mean age 62 (SD 12), mean weight 80kg (SD 15), 22% female were recruited with co-morbidities of hypertension-53%, dyslipidemia-52%, diabetes-20% and prior MI-23%. Index diagnosis was: non ST-elevation ACS-62% and ST-elevation MI (STEMI)-38%. Admission and discharge use of medications were: aspirin-36 & 95%, clopidogrel-21 & 94%, statins-37 & 84%, beta-blockers-30 & 76% and ACE inhibitors/ARBs-34 & 67%. 2349 stents were used (DES-52%; France-33%, Spain-64%, UK-55%) with 58% of patients receiving only one. A total of 51% of patients were transferred at least once between study and another hospital, France-54%, Spain-46%, UK-54%. Admission to PCI at study hospital was: median 2 days (IQR 1-5 days) for non-ST ACS patients, (65% 3 days or less; France-87%, Spain-72%, UK-38%); and median 0 days (IQR 0-2 days) for STEMI patients, (73% 1 day or less; France-82%, Spain-74%, UK-58%). Total stay was median 6 days (IQR 4 – 9) for both cohorts. QoL at hospital discharge using EQ-5D health state index was: median 0.85 (IQR 0.71-1.00) with 1 representing perfect health, (France-0.85 (0.73-1.00), Spain-0.85 (0.73-1.00), UK-0.81 (0.68-1.00)). Conclusion: These data indicate geographic and case mix variation in management of ACS patients, including use of DES, but with uniform early QoL findings. Use of pharmacotherapies is high. Long term QoL will assess the impact of variations, but these early findings are useful benchmarks to guide service provision, focus treatment guidelines and validate clinical trials.