OBJECTIVES: Irrational antibiotic usage is still common in Turkey and antibiotics are still the most commonly used drug in Turkey. Our aim in this study was to evaluate the effects of generic drug usage in inpatient clinics in Turkey, icompared to brand names. METHODS:  Data was collected from one university hospital, internal medicine inpatient service for 1 month. A total of 62 patients were treated with an antibiotic. The antibiotic's name, dosage and the duration of use were recorded by the nurses. The price of the antibiotics were extracted from the Ministry of Health's official price list. We compared the cost of the bio-equivalent and the cheapest generic drugs with the original drugs. RESULTS: During the month, the cost of the antibiotics used at the internal medicine inpatient clinic was €1136, compared to the cheapst generics, which was €1013. In this clinic, €2,2 per patient more was paid for the brand name antibiotics each month. If the 1400-1600 patients being treated with antibiotic in this hospital per year are considered, an average of €3300/month or €39,600/year is being paid for brand name antibiotics. CONCLUSION: Considering antibiotics are the most common used medication in Turkey (17% of total drug usage), it can easily be understood how the use of Brand Name drugs rather than Generics would lead to a vast economic burden. This shows the importance of promoting the use of generic antibiotics and the need for cost-minimalization analysis.