OBJECTIVES: To assess clinical efficacy and economic effectiveness of Azithromycin compared with other antibiotics for community-acquired pneumonia (CAP) and sinusitis treatment. METHODS: Decision tree was used to calculate costs of antibiotic treatment. The chance nodes included treatment failures and introduction of second-line therapy or hospitalization. Transition probabilities were obtained from clinical trials. Preferred antibiotics for comparison with azithromycin(extended release, 2.0 g.) and for second-line treatment were chosen by experts in a survey. Medical care costs were derived from Moscow mandatory medical insurance system. Costs of the medications were obtained from consumer prices database. Sensitivity analysis was carried out. RESULTS: Clinical efficacy was equal.  Costs of CAP treatment were 4390 rub (142.14$) for Amoxycillin and clavulanic acid,  5386 Rub ($174.39)  for Cefuroxime axetil and 4053 Rub ($131.23)  for Azithromycin. Costs of sinusitis treatment were 3637(117.76),  3728 (120.71) and 3570 rub ($115,59) for Amoxycillin and clavulanic acid, Cefuroxime axetil and Azithromycin respectively. CONCLUSIONS: Azithromycin is  more efficient option for CAP and sinusitis treatment than Cefuroxime axetil and Amoxycillin and clavulanic acid in Russia.