The study explored how the meaning of prosocial behavior changes over toddlerhood. Sixty-five 18- and 30-month-olds could help an adult in 3 contexts: instrumental (action based), empathic (emotion based), and altruistic (costly). Children at both ages helped readily in instrumental tasks. For 18-month-olds, empathic helping was significantly more difficult than instrumental helping and required greater communication from the adult about her needs. Altruistic helping, which involved giving up an object of the child?s own, was the most difficult for children at both ages. Findings suggest that over the 2nd year of life, prosocial behavior develops from relying on action understanding and explicit communications to understanding others? emotions from subtle cues. Developmental trajectories of social-cognitive and motivational components of early helping are discussed.