A Markov model was developed to determine the cost of treating patients with stage IIIB or IV metastatic breast cancer with 5-fluorouracil, doxorubicin, and cyclophosphamide (FAC) and dexrazoxane (administered after six courses of FAC) versus FAC alone. The primary end point in our economic study was cost per cardiac event avoided. Cost per life-year saved was also calculated, even though the survival advantage needs to be confirmed in follow-up studies. The model incorporated the direct medical costs of treating patients with chemotherapy, as well as the costs associated with treatment of any cardiac events that occurred. Data were collected for this analysis from several sources, including completed clinical trials on FAC plus dexrazoxane versus FAC plus placebo (obtained from two patient groups randomized at different time points), a panel of three oncologists, and a panel of three cardiologists. Analyses showed that therapy with dexrazoxane costs $5661.77 per cardiac event prevented. Sensitivity analyses on model variables were performed and showed that the basic results of the model did not change when parameters were varied. The clinical efficacy and cost-effectiveness of dexrazoxane as shown by the results of the current study encourage further investigation of the uses of dexrazoxane in other populations and against other comparators.