Pervasive systems are complex distributed systems containing heterogeneous and mobile devices, services and applications. Policy-based management is an effective approach for managing these systems. The dynamism of a pervasive system due to mobility of devices and applications makes policy specification and management a difficult problem. Policies need to be modified when devices and applications are added, removed or migrated across pervasive systems. This causes significant policy management overhead and improper management may lead to policy conflicts, cycles and other undesirable system behaviors. In this paper, we present a role-based approach for managing pervasive systems. Roles group related entities and enable logical separation of entities from policies. Policies and entities are assigned to roles and every entity belonging to a role enforces policies assigned to that role. Policies and entities can be independently modified and this flexibility simplifies policy management. Roles are further organized into hierarchies that enable policy reuse. We present our management framework and middleware based on roles that is being developed for managing our prototype pervasive system.