Recent research has established that contrast can exert a powerful effect on early word learning. This study examined the role of contrast in young children's ability to learn proper names. Preschoolers heard a novel word for an unfamiliar stuffed animal in the presence of a second stuffed animal of either the same or a different kind. Children received contrastive information indicating that the word did not apply to the second animal. Children were more likely to interpret the word as a proper name if the second animal belonged to the same kind as the target than if it belonged to a different kind. Children did not appear to make a proper name interpretation in a control condition in which the second animal was not present, providing no contrastive information. The results reveal the strength of within-kind contrastive information to foster children's acquisition of proper names, highlighting the potency of comparison processes in early word learning.