OBJECTIVE: A pharmacoeconomic analysis was carried out comparing the efficacy of two treatment options for community acquired pneumonia (CAP): Telithromycin and Clarithromycin. METHODS: Retrospective analysis using a decision tree model. The efficacy of the two treatment options was estimated from a randomised, double-blind clinical trial, in which 800 mg/day of Telithromycin was compared to 1000 mg/day of Clarithromycin in patients with CAP (162 and 156 respectively). The utilisation of resources was captured in the clinical trial with estimated Spanish sources, and the unit costs from a Spanish health costs database. Costs were evaluated for the acquisition of antibiotic treatments, change of antibiotic due to therapeutic failure, hospital admissions, adverse reactions treatment, primary care visits, tests and indirect costs (working days lost). The model was validated by a panel of Spanish clinical experts. RESULTS: As there were no significant differences in efficacy between the treatment options (clinical cure rate 88.3% and 88.5% respectively), a cost minimisation analysis was performed. In the base case, the average cost of the disease per patient was €308.29 with Telithromycin and €331.5 with Clarithromycin (a difference of €23.21). The results were stable in the sensitivity analysis, with differences favourable to Telithromycin ranging between €5.50 and €45.45. CONCLUSIONS: Telithromycin results in a cost saving of up to €45.45 per patient with CAP compared to Clarithromycin.