Ubiquitous Quality of Service(QoS)-aware applications, such as e-business or multimedia delivery are becoming available anywhere anytime. In the past decade, also QoS-oriented middleware services, assisting QoS-aware applications with different aspects of QoS provisions, have been proposed. Assuming the availability of these middleware services, in this paper, we present the application to middleware service translation system. This system helps an application developer to develop a QoS-aware application which can be deployedflexibly andefficiently in ubiquitous environments with different available middleware services. We introduce the middleware abstraction layer (MAL) between the application view of middleware and the specific middleware implementations. The translation system assists the QoS-aware application in two phases: (1) environment-independent translation, and (2) environment-dependent translation. The first phase maps the QoS-aware application to configurations of middleware services without indication of specific implementations, to satisfy the qualitative QoS requirements. Its result is the portable MAL representation. The secondphase helps the application developer to customize the MAL representation within a specific deployment environment. It deals with (a) mapping of MAL representation into configurations of specific middleware implementations, and (b) mapping of application quantitative QoS requirements into specific middleware implementation’s expected parameters. Our translation system facilitates the rapidgrowth of QoS-aware applications in the ubiquitous environments.