Workflows used in business processes and distributed computing environments have supported service automation by connecting many tasks with rules and/or orderings. To adapt these workflows to ubiquitous computing, we must specify the context information on their transition conditions. In this paper, we propose uWDL, Ubiquitous Workflow Description Language, to specify context information on the transition constraints of a workflow in order to support adaptive services, and we designed a structural context model to express the context information in uWDL. Furthermore, uWDL is designed based on Web services, which are standardized and independent of various heterogeneous platforms, protocols, and languages. In order to verify the effectiveness of uWDL, we designed and implemented a scenario described with uWDL, and demonstrated that the uWDL system provides users with autonomic services in ubiquitous computing environments.