OBJECTIVES: To explore the use of generic medicines amongst elderly in Belgium. Therefore, market shares by volume of generic medicines for the different ATC drug classes are calculated. Possible savings of increased use of 20 generic medicines, based on the top expenditures in the off-patent market in Belgium, are calculated. METHODS: Data on the use of medicines in the elderly population were derived from a regional community pharmacy database which collects data of dispensed prescription medicines in a selection of Belgian public pharmacies. The variables delivered were the name, the ATC-code, the number of packages sold in 2010, the average price and the defined daily dose. Savings were calculated using weighted average price levels for both originator and generic medicines. Three scenarios of potential savings were calculated: a 5%, 10% or 20% increase of generic market shares of the selected medicines. RESULTS: The generic market share for elderly in 2010 was 23.1%, while this was 23.7% for the total Belgian population in 2009. Generic market shares for the five most important ATC drug classes (A, B, C, M and N) varied from 8.81% for class B to 63.70% for class A. Market shares of the 20 drugs used in the exercise varied from 1.11% to 96.32%. Increasing market shares of generic medicines could generate savings varying from 1.80% (5% increase) to 6.39% (20% increase) of the public expenditure on originator medicines. In a situation where generic market shares would reach 95%, estimated savings could even be 20.15% of the public expenditure on original medicines for this selection of medicines. CONCLUSIONS: The full potential of generic medicines in the elderly population has not yet been realized in Belgium. Additional incentives for physicians, pharmacists and patients are needed as an increased use of generic medicines by elderly could generate significant savings.