OBJECTIVES: The purpose of the study was to evaluate economic and health consequences of first line antibiotics treatment for inpatient therapy in Mexican patients with acute exacerbations of chronic bronchitis (AECB) from the healthcare payer's perspective. METHODS: A cost – effectiveness assessment was performed employing two economic models. First, a three-month decision tree model was used to compare costs and effectiveness associated to acute exacerbations treatments. Second, a one-year Markov model was created to compare costs and effectiveness associated to AECB recurrences. Model comparators were: gemifloxacin 320mg/day, moxifloxacin 400mg/day, levofloxacin 500mg/day, ceftriaxone 1gr/day, gatifloxacin 400mg/day, clarithromycin 1,000mg/day and cefuroxime 1,000mg/day. The effectiveness measures were the % of clinical success and the number of free months of recurrences/hospitalizations. Resource use data was obtained from hospital records inside the General Regional Hospital No. 1 “Gabriel Mancera” at the Social Security Mexican Institute (IMSS) in Mexico City (n=117). All drug prices and resource use costs were taken from official institutional databases from the IMSS. One-way and probabilistic sensitivity analyses were performed and components analyses were elaborated. RESULTS: Gemifloxacin showed the lowest expected costs (US$2,750.2); the highest % of clinical success among all alternatives (97.5%) and the shorter hospitalization stay length (approximately 6.1-days). The total days reduction generated by gemifloxacin could reduce total hospitalization costs in $US1,269.5 per acute exacerbation. Markov model results for free months of recurrences showed that gemifloxacin first line therapy for AECB could give patients in average 11.1-free months of recurrences/hospitalizations followed of ceftriaxone (10.9-months) and moxifloxacin (10.5-months). The results were robust to first-order Monte Carlo simulations and acceptability curves. CONCLUSION: Gemifloxacin is the most cost effective first line treatment for inpatients with AEBC, because its high effectiveness, significant inpatients day's reduction and more free months of recurrences. These results could be used by Mexican decision-makers to generate future cost-containment strategies.