The choice of antibiotic for treatment of community-acquired pneumonia (CAP) is performed without bacteriologic analysis in 100% cases. Utilization antibiotic data will help to realize its real tendency and capabilities. OBJECTIVES: The study purpose was to investigate used antibiotics in correlation with cost-effectiveness in CAP. METHODS: The study was performed on analyzing of 800 patient files with CAP from out-patient departments. The diagnosis was based on physical examination, X-ray and laboratory data. The type of antimicrobial, its doses, duration of treatment until recovery, and index of cost/effectiveness were examined in two groups: at patients before 60 years old (I) and over 60 years with or without associated diseases (II). RESULTS: Amino-penicillins were used in 32% in both groups, macrolides and azalides in 27% (I) and 23% (II), fluoroquinolones - in 22% (I) and 16% (II), aminoglycosides in 8% (I) and in 14% (II) and others. The mostly often-used combinations were trimethoprim/sulfamethoxazole with ampicillin or ciprofloxacin. Efficiency of used antibiotics was found as following: azithromycin was 100% in both groups, co-amoxiclav - 85% (I) and 100% (II), midecamycin 85% in both, ampicillin 91% (I) and 80% (II), spiramycin - 82% (I) and 74% (II), while efficiency of ciprofloxacin was only 67% (I) and 81% (II), of erythromycin 78% (I) and 41% (II), gentamycin above 40% in both, trimethoprim/sulfamethoxazole 46% (II). The best cost/effectiveness ratio was calculated for ampicillin, azithromycin, medicamycin in both groups. The treatment with ciprofloxacin and co-amoxiclav was less cost-effective in group I. CONCLUSION: The most commonly used antibiotics for treatment of CAP were ampicillin and macrolides. This type of treatment is adequate from medical and economic points of view. Using of fluoroquinolones and aminoglycosides should be limited by gram-negative etiology.