INTRODUCTION: Elderly patients undergoing coronary bypass surgery after acute myocardial infarction represent a distinct, high risk subgroup. We sought to identify independent risk factors for mortality in a series of patients operated on in our hospital. METHODS: The case records of 499 consecutive patients greater than 70 years were identified, and 94 of these patients underwent urgent/emergent coronary bypass surgery within 7 days of acute myocardial infarction. Patients received either cold (4°C) or tepid (32°C) cardioplegia for myocardial protection. RESULTS: Mortality for the tepid cardioplegia group was 0/33, and the mortality for the cold cardioplegia group was 12/61 (0% vs. 20%, p equals 0.003). Multivariate analysis demonstrated left ventricular dysfunction and cold blood cardioplegia to be independent predictors of mortality. CONCLUSION: The type of myocardial protection technique is a significant predictor of mortality, and tepid cardioplegia may provide significant advantages to this high risk patient population.