BACKGROUND: Acute coronary syndromes (ACS) without ST elevation are a frequent cause of hospital admission, myocardial infarction and death. AIM: To explore the role of the ECG in stratifying ACS patients. DESIGN: Prospective, centrally-coordinated multicentre registry involving 56 centres throughout the UK. METHODS: Consecutive patients admitted with ACS without ST elevation on the presenting ECG (n = 1046) were followed for 6 months. A subgroup (n = 653) were flagged with the UK Office for National Statistics and followed-up for death over 4 years. RESULTS: Mean follow-up for the group as a whole was 2.4 years. In the first 6 months, the death rate was 7.3%. Survival at 1 year was 90.8% (95%CI 88.2%-92.8%); at 45 months it was 77.8% (95%CI 74.1%-81.1%). We compared data in those with ST depression or bundle branch block on the admission ECG (n = 304, 29%) with those with T wave inversion, Q waves and minor ST segment changes (n = 576, 55%) and those with a normal ECG (n = 166, 16%). Their respective incidences of death were 15%, 5% and 2% (p < 0.01) at 6 months, and 38%, 22% and 7% (p < 0.01) at 4 years. DISCUSSION: Rates of adverse events are high in patients admitted to UK hospitals with ACS without ST elevation. The ECG remains a very important and simple discriminator of both short- and long-term risk, enabling more aggressive, proven therapies to be targeted towards those at highest risk.