To charitable organizations, catalogue mail order firms offer an opportunity to expand both database and revenue. But an offer must be made very carefully since motivation for a donation (altruistic) seems incompatible with that of a purchase (economic). This research is designed to study the impact of sending a catalogue offer to actual donors on their subsequent donation behavior. An experimental study with a French charitable institution shows that while mail order sales do indeed erode traditional public canvassing campaigns, this erosion nonetheless remains limited. It also reveals that traditional donors seem to be reluctant to use this commercial approach.