OBJECTIVES: To assess the cost-effectiveness of amoxicillin clavunate compared to amoxicillin at primary care level in Turkey for community acquired pneumonia, acute rhinosinusitis, tonsillopharyngitis, and acute otitis media.  METHODS: As proposed by the guidelines for the treatment of diseases costs have been determined through applying cost of illness methodology. The agents have been calculated by evaluating all brands and forms over continuous doses. The perspective of the reimbursement institutions in Turkey has been reflected upon the costs. As a value of effectiveness, the rate of completing the treatment has been chosen. The success rate of completing the treatment determined as 2 doses and 3 doses per day has been gathered from the literature. The completion level of the treatment for 2 doses per day is 68% and for the agents used for 3 doses, it is 50%. RESULTS: In terms of incremental cost per additional completing doses,  amoxicillin clavulanate  is cost saving versus amoxicillin group for the treatment of community acquired pneumonia (-113.43 TL), acute rhinosinusitis (-70.73 TL), acute otitis media (-70.73 TL), tonsillopharyngitis (-52.06 TL). CONCLUSIONS: According to the results derived from the comparison between the costs and effectiveness values; for the each illness at primary care, the use of amoxicillin clavulanate is cost saving in order to complete the treatment successfully.