Synchronization is an important aspect of the design and implementation of distributed multimedia database systems. In this chapter, we first examine the models that have been proposed in the literature to specify multimedia and multi-stream synchronization and the methods to implement synchronization mechanisms in distributed multimedia database systems. Their strengths and limitations have been compared, and the issues about time uncertainty and interactivity in multimedia and multi-stream synchronization specification and implementation are discussed. Moreover, we use an example to show how to incorporate a synchronization agent into a distributed multimedia database system. Finally, we discuss the trend of future research and development of this topic.