—This paper presents an approach for modeling and associating Policies to services' based appjalications. It proposes to extend the SOD-M model driven method with (i) the π-SCM, a Policy services' composition meta-model for representing non-functional constraints associated to services' based applications; (ii) the π-PEWS meta-model providing guidelines for expressing the composition and the policies; and, (iii) model to model and model to text transformation rules for semi-automatizing the implementation of reliable services' compositions. As will be shown within our environment implementing these meta models and rules, one may represent both systems' cross-cutting aspects (e.g., exception handling for describing what to do when a service is not available, recovery, persistence aspects) and constraints associated to services, that must be respected for using them (e.g., the fact that a service requires an authentication protocol for executing a method).