The present study investigated the link between number-word learning and changes in the childs attention and memory for implicit number information. 71 children (ages 2-2 to 4-9) were asked, without number words, to replicate sets of 1 to 4 objects. Childrens performance on the set-replication task was correlated with cardinal number-word knowledge, independent of age, and also independent of target set size (e.g., three-knowers did better than two-knowers on all set sizes, not just on sets of 3). Analysis of the children's vocabulary scores suggests that the differences are not due to general language development. Findings suggest that number-word learning is closely tied to the development of nonlinguistic numerical cognition.