OBJECTIVES: To investigate doctors' prescribing behavior in Greece. METHODS: Data was derived from a closed questionnaire applied to a random stratified sample consisting of 1463 doctors. The response rate was 82.3%. Analysis of categorical data concerned the calculation of descriptive measures, frequencies and relative frequencies, and test of independence using Chi-square test. RESULTS: Drugs' effectiveness, appearance of side effects and drug cost for the patient have been shown the most important criteria for prescription. Younger and less experienced doctors seem to take more into account drug cost, dosage and side effects. Scientific journals, medical conferences and literature review are referred as the main information sources about drug's effectiveness. As less significant sources of influence are mentioned the sales' representatives of pharmaceutical companies and the internet. It is revealed that sales' representatives of pharmaceutical companies don't affect physicians' prescription decision, due to the fact that they believe that the information sales' representatives of pharmaceutical companies provide, focuses mainly in drugs' advantages. Regarding the internet use it seems that Greek doctors, mainly the older ones, are not familiar with the use of new technologies and they prefer printed information from journals and literature. Furthermore, it is mentioned that any attempt of reforming drugs' reimbursement policy doesn't affect the volume and the cost of prescribing. In general, physicians have a positive opinion about generics, even though only 3.6% prescribes generics frequently. Male doctors tend to prescribe generics more often. The majority of doctor's believe that the price of new drugs is too high compared to their improved effectiveness. CONCLUSION: Knowledge of the profile prescription of doctors could be a useful tool for supply – side drug policy interventions. Such studies combined with patients reported outcomes could contribute to the qualitative and quantitative evaluation of drugs' policy.