Abstract: Managing the number of destination nodes for multicasting services is an important challenge in communication networks. When a Multicast Multichannel Path (MMCP) transmits packets from a source node to a group of destination nodes it might be possible the number of destination nodes change. This means that during a multicast data transmission session, either removing some current destination nodes or adding some new destination nodes can be happen. Removing a current destination node loses packets which are being transmitted to that node. Therefore, increasing or decreasing the number of destination nodes causes that the router compulsorily changes or re-computes the current multicast paths. Adding or removing the destination nodes must be done by a dynamic routing algorithms because static routing algorithms do not support dynamic changes in network topology. Re-computing multicasting path must be dynamically done because static computations may disconnect multicasting path and halt data transmission. When a current path is replaced with another new path, some packets cannot be forwarded to their destinations and they will be lost. This affair removes packets and then wastes bandwidth. In this study, we will present a new Dynamic Routing Algorithm, Optimal Dy-namic Multicast Multichannel Routing (ODMMR) which prevents from losing packets and wasting network resources. Our new algorithm is based on the multichannel constraint-based routing (a traffic engineering approach) and supports Quality of Services (QoS). Computational results and simulation analysis will show that our new algorithm is more efficient than other available routing algorithms.