Today, Service Oriented Architectures (SOA) are being widely deployed to improve systems development and interoperability. In addition, the increasing use of mobile devices and infrastructure has enabled users to access services from any location and any time. The convergence of mobile technologies and service paradigm has promoted the birth of a new design and development paradigm known as Context-Aware Service (CAS). CAS based systems are context-aware and therefore they can offer pertinent services for their users depending on their context. Dealing with such systems requires an approach that addresses challenges such as context management and service adaptation to the context. In this paper, we present how can the development process of Context-Aware Service Oriented Systems (CASOS) benefit from the model and aspect paradigms?