OBJECTIVES: The community-acquired respiratory tract infections (CARTI) are the most frequent indicators for antibacterial preparations prescription, that requires significant costs. Traditionally, penicillins and macrolids are used for it. Certain perspectives of CARTI treatment are connected with the new generation "respiratory" fluoroquinolones use, that have high antibacterial activity in relation to S. pneumoniae, but are rather expensive, especially in Ukraine. The aim of this work was comparative evaluation of costs efficiency for patients treatment with community-acquired pneumonia (CAP) and exacerbations of chronic bronchitis (ECT) with antibacterial preparations such as fluoroquinolone moxifloxacin versus macrolid clarithromycin for the optimal use of patient’s or state’s financial expenses grounding. METHODS: cost-minimization and sensitive analysis. RESULTS: The results of G. Hoffken, H.P. Meyer, K. Sprenger et al.(1999) have been used for pharmacoeconomic evaluation. In the trial 531 patients took place and it lasted 10 days. The treatment regimes were: moxifloxacin (200 mg / day); moxifloxacin (400 mg / day); clarithromycin (500 mg / two times a day). For pharmacoeconomic evaluation of ECT treatment the results of trial (R. Wilson, R. Kubin, I. Ballin et al., 1999) have been used: 649 patients took part in trial. The trial lasted 7 days. The treatment regimes were: moxifloxacin (400 mg / one time a day) for 5 days, clarithromycin (500 mg / two times a day) for 7 days. Efficacy of moxifloxacin and clarithromycin for CAP and ECT was equal. CONCLUSIONS: The results of “cost-minimization” analysis are sensitive to prices for drugs changing, and it does not create stable advantages for clarithromycin. In case of maximal price for drugs, it is moxifloxacin that has advantages.