OBJECTIVES: The aim of this study is to describe the experience with the Belgian policy that obliges physicians to prescribe minimum quota of cheap medicines and to document the outcomes of this policy using publicly available data. METHODS: Data were obtained from yearly feedback reports of the policy on the website of the Belgian third-party payer (RIZIV/INAMI) which were sent to all physicians. Data were derived from Farmanet, a database where all data of prescriptions of reimbursed medicines from all physicians in Belgium are collected. RESULTS: All groups of general practitioners, specialists and dentists reached their minimum percentages every year from 2006 until 2009. The percentage of cheap medicines (in DDD) increased from 22.9% in January 2005 to 44.2% of all prescribed medicines in ambulatory care in December 2009. The percentage of generic medicines increased from 12.10% in 2004 to 24.03% of all prescribed medicines in ambulatory care in 2008. When a physician prescribed a cheap medicine, this was an original medicine whose price had dropped to the reference price level in 41.5% of cases in August 2009. CONCLUSIONS: The policy of prescribing quota for cheap medicines was not only associated with increased prescribing of generic medicines during 2004-2008, but also increased prescribing of original medicines whose price had dropped to the reference price level. The potential for prescribing generic medicines has not yet been fully met in Belgium. Despite the success of the policy, adjustments are desirable, especially with respect to the broad definition of cheap medicines. Given the fact that all groups of physicians reached their minimum quota quite easily together with the increased possibility of prescribing cheap medicines due to the entrance of new, generic medicines, the government decided to raise the minimum criteria in 2011.