One of the most compelling features of Xen virtualization is the ability to migrate a domainU guest from one host system to another. Of particular significance, however, is Xen's ability to perform live migrations whereby a running guest domainU system is moved from one system to another such that there is only an imperceptible interruption in service. In this chapter we will discuss the requirements for performing live Xen domainU migrations before walking through an example live migration.