Object mobility is the basis for highly dynamic distributed applications. This paper presents the design and implementation of mobile objects on the basis of the CORBA standard. Our system is compatible to the CORBA Life-Cycle–Service specification and thus provides object migration between different language environments and computer systems. Unlike others, our Life-Cycle–Service implementation does not need vendor-specific extensions and just relies on standard CORBA features like servant managers and value types. Our implementation is portable; objects can migrate even between different ORBs. It supports object developers with a simple programming model that defines the state of an object as value type, provides coordination of concurrent threads in case of migration, and takes care of location-independent object addressing. Additionally we seamlessly integrated our implementation with a dynamic code-loading service.