Background: The health expenditure increases over time, while drug cost takes 30% of total health expenditure. An alternative to reduce drug cost is by using generic medicines. This research aimed to count the drug cost saving potential by the use of generic drugs. Methods: A cross sectional non intervention study has been conducted in five hospitals in DKI Jakarta province. Result: Showed the total number of prescription prescribed from all hospitals during 6 months was 72,492. From 1600 prescription analyzed there were 5,891 items of drug. Five of ten drugs which were often prescribed had no generic match. The highest price comparison of branded and generic drugs was in antibiotic groups (59 times). The price of prescription can be reduces Rp.28,733 per each and the cost saving potential from 6 months period in 5 hospitals were Rp.2,082,912,636 by using generic drugs. The Conclusionof this research was generic drug use can save drug cost approximately Rp.28,000 per prescription or equal to about 2 billion for 6 months.