Abstract: Selfishness issue is one of big challenges of current application-layer multicast techniques. The selfish participants might stop forwarding data accidentally or deliberately, which will affect the overall streaming quality. To address the selfishness issue in the application-layer multicast, an altruism driven application-layer multicast (ADALM) is presented. ADALM defines an altruism value for each node associative to its contributions to the system. The multicast tree is constructed to place the nodes with greater altruism value at the higher layer of the tree. As compared with other studies in this area, ADALM exhibits innovative advantages in both altruism value computation and multicast tree construction. Firstly, the nodes altruism value is generated from the feedback from its parent and children, which enables the system to detect the selfish nodes effectively. Peers dont need the extra probe messages to measure the QoS of their neighbors. During the process of tree construction and maintenance, only O(lg N) nodes needs to be adjusted. Lastly, the altruism value calculation and multicast tree construction are realized in a decentralized manner without any single point of failure. Simulation results show that even with a significant portion of nodes being selfish, ADALM is able to build a dissemination tree that provides high overall streaming quality with low control overhead.