OBJECTIVES: We investigated drug usage in Ankara and estimated the cost of unsused medicines to social security agencies. METHODS: A questionnaire was structured to find out the drug storage profile in 329 in 2004, 215 families in 2006, living in central Ankara and compare drug usage behaviour between 2 years. The questionnaire had two parts, the first included the demographic properties of the families. The second part included for any drug found in their house, the size of the package, the unused amount of the drug and expiry date of drugs. RESULTS: About 90% of the families receive drugs from social security agencies in 2004, 99% in 2006. The mostly found three drugs were Aspirin® (acetyl salicilic acid), Vermidon ® (paracetamole), and Mesulide ® (nimesulide) in 2004, And Vermidon ®(paracetamole), Aspirin® (acetyl salicilic acid), Majezik® ( Flurbiprofen) in 2006. When ingredients were analyized, the three, mostly found, active compounds were paracetamole, multivitamin preparates, and acetyl salisilic acid in 2004, and paracetamole, acetyl salisilic acid, multivitamin preparates in 2006. The drugs with the largest amount of packaging were found to be the most wasted. In 2006, 53% of drugs were completely or partially unused. Thirty-one percent of them were completely unused. Among the drugs wasted some antibiotics such as sultamicillin and co-amoxilav were higher rate. CONCLUSION: This survey shows that there is a great deal of drug waste (product and $), in Turkey. We estimated that Turkish Social Security Agencies are wasting more than 1 billion US $ just for never used drugs and another 1 billion US $ for partially used drugs (Turkish drug market is about 7 billion US $). Drug expenditure is, by far, the highest proportion of the Turkish health costs expenditure (about 60% total health cost expendature), and it creates a heavy financial burden on the Turkish government.