OBJECTIVES: To assess the clinical effectiveness and economic consequences of telithromycin or clarithromycin in CAP treatment from public payer perspective in Poland. METHODS: Results of a systematic review of published clinical trials selected in accordance with EBM criteria were used to assess effectiveness and safety of the antibiotics in CAP treatment. The economic consequences for public payer for therapy of individual patient in case of clarithromycin replacement by Ketek (telithromycin) were calculated. In this analysis it was assumed that only pharmacotherapy costs and CAP hospitalization costs differed; other costs were assumed to be the same irrelevant to the antibiotic used. An assumption was made that level of pharmacotherapy reimbursement in case of treatment with both telithromycin and clarithromycin would be the same, public payer costs for DDD were calculated. Costs of CAP hospitalization varied on number of admissions during 1 month of follow-up period. RESULTS: Clinical effects of the two drugs were similar and no significant differences in effectiveness or safety were found in pooled data from two randomized clinical trials. Telithromycin treatment was associated with significantly fewer CAP-related hospitalizations compared with clarithromycin (1.6%vs3.6% patients admitted, respectively). CAP-related hospital costs per patient were much lower for telithromycin treatment compared with clarithromycin (35.5pln(8.45E)vs79.2pln(18.8E) respectively). Taking into account reimbursement of pharmacotherapy and costs of hospitalization, public payer savings when using telithromycin in place of claritromycin could be as high as 33pln(7.8E)-50pln(12E)/patient (based on sensitivity analysis). This lead to high annual savings for public payer. CONCLUSION: Ketek (telithromycin) in place of clarithromycin lead to significant savings for public payer in CAP treatment in Poland.