BACKGROUND: The prognostic value of blood pressure measured during hospitalization after acute myocardial infarction (MI) has not been investigated, particularly with regard to arrhythmic death. METHODS: A total of 3311 placebo patients (2612 men, median age 64 years; range 23-92) from the EMIAT, CAMIAT, SWORD, TRACE and DIAMOND-MI studies with left ventricular ejection fraction less than 40% or asymptomatic ventricular arrhythmia surviving more than 45 days after MI were pooled. Systolic and diastolic blood pressures and pulse pressures were measured soon after MI (median 6 days, range 0-53 days). Mortality up to 2 years was examined using Cox regression. RESULTS: At the 2-year follow-up, after adjustment for age, sex, smoking, previous MI, hypertension, heart rate, New York Heart Association functional class, baseline treatments, study effect and diastolic blood pressure, reduced systolic blood pressure measured during hospitalization after acute MI significantly increased the risk of all-cause mortality [hazard ratio (HR) for 10% increase in systolic blood pressure 0.80, 95% confidence interval (CI) 0.71-0.90; P < 0.001] and arrhythmic mortality (HR 0.73, 95% CI 0.61-0.86; P = 0.001). Reduced diastolic blood pressure significantly increased the risk of all-cause mortality (HR 0.87, 95% CI 0.77-0.98; P = 0.02) and arrhythmic mortality (HR 0.80, 95% CI 0.68-0.93; P = 0.005). CONCLUSION: In post-MI patients with left ventricular ejection fraction less than 40% or asymptomatic ventricular arrhythmia, reduced blood pressure measured during hospitalization after MI significantly predicts all-cause mortality and arrhythmic mortality, and can be reliably used to identify patients who are at risk of dying after MI.