OBJECTIVES: Linezolid is a new antibiotic, active against Gram-positive bacteria and available in intravenous and oral formulations with a bioavailability of 100%. The aim of this analysis is to carry out an economic evaluation of linezolid (LZD) vs teicoplanin (TEI) for the treatment of infections produced by Gram-positive bacteria. METHODS: A cost-effectiveness analysis was performed by building a decision analytical model. Effectiveness data were obtained from a multicenter randomized trial showing that LZD had significantly better efficacy than TEI (95.5% vs 87.6%, p=0.005) in treating infections caused by Gram-positive bacteria (ICCAC 2001; poster L-1481). Healthcare resource utilization after the use of both antibiotics was taken from the aforementioned clinical trial (ECCMID 2002; poster P-486) and a local expert panel. Only direct medical costs were included in the model (drug acquisition, length of hospital stay, nursing time for administration of drugs, diagnostic procedures and treatment of therapeutic failures). Drug acquisition cost data were obtained from official sources while the rest of the data were taken from a national healthcare costs database . The perspective selected for this analysis was hospital assistance and the time horizon chosen was for 28 days, the maximum time that patients were hospitalized in the referenced clinical trial. RESULT: Total cost/patient was lower with LZD versus TEI (€5,462.6 vs €5,739.8) as well as the cost/effectiveness ratio: €5,720 vs €6,552.3 per each successfully cured patient. CONCLUSIONS: This pharmacoeconomic analysis demonstrates that LZD is a more efficient therapeutic option than TEI, as it presents a lower cost/effectiveness ratio. Moreover, as LZD produces better clinical results with less associated costs, it is a " dominant " option over TEI and therefore LZD could be considered as the therapeutic alternative of choice in the treatment of infections caused by Gram-positive bacteria in the hospital.