OBJECTIVE: Invasive mycoses are associated with high mortality, therefore consuming important health care resources. Cost-effectiveness of voriconazole vs. amphotericin B deoxycholate (CAB) for the primary treatment of invasive aspergillosis (IA) was evaluated using data from a randomized comparative trial (Herbrecht, NEJM 2002), that showed the superiority of voriconazole in terms of clinical response, survival and safety when used as primary therapy for IA. METHODS: A model for analytical decision was designed based on the information provided by this clinical study. Changes in the antifungal treatment due to lack of response, as well as renal or hepatic toxicity with the initial treatment were assessed, considering direct medical costs only, reported in Argentine pesos. RESULTS: Average total treatment cost in the voriconazole arm was $44,040 vs. $45,428 in the CAB arm. Using the model assumptions (efficacy: 52.8% for voriconazole, 31.6% for CAB) voriconazole was the dominant treatment vs. CAB as primary therapy, with a cost per successfully treated patient of $83,444.96 vs. $143,858.26 respectively. One-way sensitivity analysis was performed in order to assess the impact of relevant key variables (cost of antifungals, cost of hospitalization, etc.) Even after changing these variables in a wide range, voriconazole was still cost-saving. CONCLUSIONS: Incremental cost-effectiveness analysis indicated that voriconazole was the dominant therapy due to both lower costs and higher efficacy.