We estimated the cost effectiveness of adding the ACE inhibitor ramipril to conventional treatment in patients with heart failure after acute myocardial infarction. These estimates were based on the Acute Infarction Ramipril Efficacy (AIRE) study and on complementary Swedish healthcare resource use data for a subset of patients. The average follow-up period was 15 months (minimum 6 months, maximum 3.8 years). The perspective of the analysis was that of the county councils (third-party payers), and we focused on the cost of drugs and hospitalisation. The marginal cost effectiveness of the treatment was estimated over 3 treatment periods: 1, 2 and 3.8 years. The cost-effectiveness ratios varied between SEK14,148 and SEK33,033 per life-year gained ($US1 = SEK7.70. Pounds 1 = SEK12.40) for the 3 treatment periods. Adding ramipril to conventional treatment for heart failure after acute myocardial infarction is therefore cost effective, and compares favourably with the cost effectiveness of other common medical therapies in the cardiovascular field.