This study investigated the current status and drug expenditure of the drug shortage prevention program in Korea. National health insurance claims data from 2001 to 2005 were analyzed for the drugs with inadequate supply, which were designated as shortage prevention drugs (SPDs). Drug use of SPDs have increased every year, but the average increase rate of drug expenditure for SPDs, 13.5% was lower than that for all the reimbursed drugs, 18.6%. Drugs with price increase based on production cost were more actively used than drugs with prescription incentives for doctors.