OBJECTIVES: Invasive aspergillosis is a life-threatening infection with a very high mortality. Voriconazole (VOR) is a broad-spectrum triazole that is active against Aspergillus species. Our objective is to carry out an economic evaluation of VOR versus Amphotericin B (AMB) for the treatment of invasive aspergillosis in Spain. METHODS: A cost-effectiveness analysis was performed through a decision analytical model. Effectiveness data were obtained from a multicenter-randomized trial showing that VOR was more effective than AMB in treating invasive aspergillosis in immunosupressed patients (Herbrecht R, et al. N Engl J Med 2002;347:408-415). Health care resource utilisation was taken from the aforementioned clinical trial and a local expert panel. Only direct medical costs were included in the model (drug acquisition, length of stay, diagnostic procedures and treatment of therapeutic failures). Drug acquisition costs were obtained from official sources, while the rest of data were taken from a national Health care-cost database. The perspective selected for this analysis was hospital assistance and the time horizon chosen was for 12 weeks, the time that patients were followed up in the referenced clinical trial. RESULTS: The probability of successful treatment of VOR was higher than with AMB (52.8 vs. 31.6 %, p<0.05), while the cost/effectiveness ratio was lower with VOR compared with AMB: €60,577 vs. €84,294 per each patient with successful outcome. CONCLUSIONS: This pharmacoeconomic analysis shows that VOR is a more efficient therapeutic option than AMB, as its cost/effectiveness ratio is lower. Therefore, VOR could be considered as the therapeutic option to be selected routinely in the treatment of invasive aspergillosis in immunosupressed patients in Spain.