In order to evaluate the cost of a strategy designed to ensure a maximal early patency rate of the coronary artery responsible for acute myocardial infarction, we retrospectively studied 112 unselected, consecutive patients, treated during the 6 hours following onset of symptoms, either by intravenous thrombolysis (group 1, n = 57) followed by coronary angiography at the 90 th minute, and if necessary rescue angioplasty, or by primary angioplasty (group 2, n = 49), or finally by simple conventional medical treatment (group 3, contraindications to thrombolysis and catheterization, n = 6). The costs of medical treatment were expressed as standard mean costs, and were compared with total hospital expenditure. The overall hospital mortality was 8.0%: 3.5% in group 1, 8.2% in group 2, and 50% in group 3. The total cost of medical procedures during the initial hospital stay was 16,684 F, identical in groups 1 and 2 (17,985 F and 16,780 F, respectively). Total hospital expenditure was 36,254 F, with no significant difference between groups 1 and 2 (34,086 F and 41,670 F, respectively), despite a tendency towards a higher cost in group 2. This tendency reflected that of a longer hospital stay for patients in group 2, due to their more severe condition, but the proportion of medical cost within the total hospital expenditure was lower than in group 1 (40% and 53%, respectively). After one year of follow-up, only one other death from a cardiac cause was reported: the supplementary expenditure amounted to 14,617 F. This maximal reperfusion strategy during the acute phase of myocardial infarction achieved a low hospital mortality and one-year mortality, without a marked excess medical cost compared to previously published estimations. Primary angioplasty appears to have allowed a certain reduction of this cost compared to thrombolysis, but the heterogeneity of the study population does not allow direct comparison of the costs of the 2 reperfusion methods. One half of the total expenditure remains directly dependent on the duration of the hospital stay.