The aim of the Medicalisation Program of the Information System was to describe the activity of hospital for budget allocation. This work concerned the whole hospitalizations in the unit of intensive care of cardiology of Dijon for a myocardial infarction (MI) during the 1st half of 1998 (59 patients). The objectives of this study were: 1) the estimate of the real cost of MI management; 2) the comparison of this cost with the reference cost, determined from the data of the National Basis of Costs (BNC); 3) the economic impact of the quality of coding. The real global cost of MI was estimated at 2,323,542 FF (average by patient: 39,382 +/- 15,718 FF). Sixty eight per cent of the costs are directly related to the standing fixed overheads; in contrast, the medical and the therapeutic acts accounted for only 32% of the estimated real cost. A 52% over-estimation was highlighted between the estimated real cost and the cost of reference (p < 0.001). The errors of coding accounted for an under-estimation of only 3.6% of the cost of reference. The duration of hospitalization was significantly higher than the stay length taken from the national reference database (12.9 +/- 5.4 versus 9.2 +/- 2.1 days; p < 0.001), and was mainly responsible for these discrepancies of costs.