OBJECTIVES: To assess the cost-effectiveness of a fixed combination of Tramadol and Acetaminophen (Tramacet*) for the management of Lower Back Pain (LBP) in Mexico. The economic evaluation was performed from a Mexican Institute of Social Security (IMSS), health service hospital perspective. METHODS: A cost-effectiveness analysis was developed with a decision model. The cost-effectiveness ratio for the therapeutic use of the fixed combination of Tramadol and acetaminophen (Tramacet*) compared to treatment with Piroxicam, Celecoxib and Diclofenac was estimated. One thousand of patients hospitalized in 2004 at the IMSS with LBP crisss were retrospectively included. This sample was used as a pattern for analyzing each alternative. A decision tree was developed based on the treatment of the disorder within the national healthcare system, and the cost for each node was determined. The costs of drug therapy, family medicine ambulatory consultations, clinical specialty consultations, rehabilitation, emergency care and hospitalization were included. Labor productivity and disability rates were also considered. Costs sources were obtained from the official and published financial and costs reports of IMSS. RESULTS: Tramacet leads to an increase in the number of patients with positive response to the treatment. Therapy with Tramacet had an annual cost of $28,640 pesos (2603.63 USD), and had the lowest hospitalization cost of all the alternatives. Also, Tramacet leads to savings for $2769 pesos (251.72 USD), compared to conventional treatment, and $648 pesos (58.90 USD)compared to Piroxicam; additionally, for every percentage point of increased improvement in the quality of life, Tramacet leads to savings of $374 pesos(34 USD). CONCLUSION: This study demonstrated that Tramacet is a cost-efficient and dominant alternative for the management of patients with chronic to acute LBP.