The purpose of these three experiments was to determine whether the visibility of previous donations to a humanitarian cause influences people’s donation to the same cause. In Study 1, conducted in bakeries, a donation box was placed near the cash register with a message soliciting donations for a humanitarian project. The moneybox was transparent or not. Results show that more donations were placed in thentransparent moneybox. Study 2 replicated these findings using face-to-face interaction.nIn Study 3, participants were solicited at home for a clothing donation, and the researchnassistant held a bag containing several items of clothing or none. It was reported thatnmore participants donated when they saw several garments in the bag. Social proof isnused to explain the results reported, and the practical interest of making visible people’s donations in humanitarian fundraising solicitation is discussed.