OBJECTIVES: . To estimate the cost difference between use and absence of use of Step-Down Strategy (SDS) with linezolid for treatment of nosocomial pneumonia (NP) caused by Gram Positive Bacteria (GPB) in Mexico, from public health care institution perspective. METHODS: . To evaluate the potential cost savings between the two strategies, a microcosting was made along three phases: (1) characterization of therapeutic protocol, (2) assessment of resources and (3) estimation of the unit costs of medical care. The temporal horizon of the analysis was set to 14 days. Costs were estimated for the year 2013, expressed in US$ and consider the following medical services: days of hospitalization, consultation with specialists, route of administration, laboratory and imaging tests as well as outpatient control, based on unit costs by level of care reported by Instituto Mexicano del Seguro Social. The frequency of use of these resources were determined from Delphi method with a panel of 10 experienced infectologists. We calculated the differences between average total costs (ATC). The stastistical significance difference between strategies was evaluated by Student's t statistic. RESULTS: . The ATC of patients using SDS was $10,116, [95%CI $9,344.6 - $10,887.3] and the ATC of patients not using this strategy was $17,251.6 [$16,379.4 - $18,123.8]. The average potential savings due the use of SDS over conventional therapy (only intravenous) are $ 7,135.6, (p<0.001). CONCLUSIONS: . The use of step down strategy could significantly reduce the costs of treatment of NP in terms of hospitalization, physician visits, laboratory and imaging tests, and drug administration, not as well the resources used in the outpatient control. In a challenging setting of cost containment policies, the use of step down strategy in suitable patients represents the opportunity to invest health care resources in a more efficient way.