Recognizing property ownership is of critical importance in social interactions, but little is known about how and when this attribute emerges. We investigated whether preschool children and adults believe that ownership of one person's property is transferred to a second person following the second person's investment of creative labor in that property. In our study, an experimenter and a participant borrowed modeling-clay objects from each other to mold into new objects. Participants were more likely to transfer ownership to the second individual after he or she invested creative labor in the object than after any other manipulations (holding the object, making small changes to it). This effect was significantly stronger in preschool children than in adults. Duration of manipulation had no effect on property-ownership transfer. Changes in the object's identity acted only as a secondary cue for children. We conclude that ownership is transferred after an investment of creative labor and that determining property ownership may be an intuitive process that emerges in early childhood.