Context-Aware applications adapt their behaviour to the current situation of the user. This information, for instance user location and user availability, is called context information. Context is delivered by distributed context sources that need to be discovered before they can be used to retrieve context. Currently, multiple context discovery mechanisms exist, exhibiting heterogeneous capabilities (e.g. communication mechanisms, and data formats), which can be available to context-aware applications at arbitrary moments during the ap-plication’s lifespan. In this paper, we discuss a middleware mechanism that en-ables a (mobile) context-aware application to interoperate transparently with different context discovery mechanisms available at run-time. The goal of the proposed mechanism is to hide the heterogeneity and availability of context discovery mechanisms for context-aware applications, thereby facilitating their development.