prosocial behavior refers to voluntary actions intended to help or benefit other individuals or group of individuals. in this article we revise experimental research on prosocial behavior in childhood. The first manifestations of prosocial behavior begin to appear after the first year of life, in simple acts such as helping an adult to reach a pencil that fell on the floor, or pointing to an object the adult is looking for. Later on they become more complex and diverse: children begin to share when another individual is at a resource disadvantage, or to cooperate with others to achieve a common goal. These experimental studies in early and middle childhood, allow to have an overview of prosocial behavior during this stage of life. The most difficult behaviors for children to achieve are those where they have to provide emotional support to someone who is sad or frustrated, or those altruistic acts that would involve a sacrifice for the child such as giving up an object of his own to improve the welfare of the other.