Web service technologies are becoming increasingly important for integrating systems and services. There is much activity and interest around standardization and usage of web service technologies. The Unified Modeling Language (UML) and the Model Driven Architecture (MDA)TM provide a framework that can be applied to web service development. This paper describes a modeldriven web service development process, where web service descriptions are imported into UML models; integrated into composite web services; and the new web service descriptions are exported. The main contributions of this paper are conversion rules between UML and web services described by Web Service Description Language (WSDL) documents and XML Schema.