OBJECTIVES: To provide an estimate of the treatment related costs of caspofungin versus liposomal amphotericin B (L-AmB) in febrile, neutropenic patients with a presumed fungal infection in the Netherlands. METHODS: : A cost-minimization analysis (CMA) was conducted based on the results of a head-to-head randomized clinical trial, in which caspofungin (70mg on day 1, 50mg daily thereafter) was compared to liposomal amphotericin B (3-5mg/kg daily). The trial showed no significant difference in success rates (adults: 33.9% for caspofungin and 33.7% for L-AmB); therefore, the two drugs can be considered equally efficacious. Main assumptions in the CMA were that no drug was spilled and that the difference in drug administration costs was negligible and could therefore be ignored. The robustness of the predicted cost-estimates was tested within several scenario analyses, including an analysis in a paediatric population. RESULTS: In the base case analysis, treatment with caspofungin resulted in cost savings of €6,564 per infected adult patient; mainly due to lower drug acquisition costs. These savings increased to €8,024 in a scenario analysis assuming that partly emptied vials will not be stored and used for another administration (ie. spillage of drugs). An additional scenario revealed that only at extreme average treatment durations of one drug, a cost neutral result would be obtained. Comparing both drugs in a paediatric population, incremental costs of caspofungin over L-AmB ranged from -€2,319 to +€1,291 for an average Dutch child aged 16 (weight 62kg; body surface area 1.725m2) and 2 (weight 12.5kg; body surface area 0.555m2) years old respectively. CONCLUSIONS: The present analysis shows that treatment with caspofungin results in considerable cost savings compared to L-AmB for the treatment of febrile, neutropenic adult patients with a presumed fungal infection in the Netherlands. In pediatric patients cost consequences are depending on body surface area.