France presents a unique situation in which the take-off of a generic drug market depends, out of regulatory incentives, on whether physicians choose a prescription method (international non-proprietary names, INN) that can lead to the delivery of these drugs and on whether patients accept them. This paper is aimed at pointing out factors explaining general practitioners' (GPs') willingness to prescribe in INN through data collected from a South-Eastern France representative sample of 600 GPs in March 2002. The main results shed light on the key-role played by GPs' information about drugs and the source which they take it from, by GPs' volume of services and caseloads, and slightly by socio-economic characteristics of patients.