In this paper, we propose a novel approach to facilitate the administration of access control policies to ensure the confidentiality of data at the level of materialized views. A materialized view stores both the definition of the view and the rows resulting from the execution of the view. Several techniques and models have been proposed to control access to databases, but to our knowledge the problem of automatically generating from access control policies defined over base relations the access control policies that are needed to control materialized views is not investigated so far. We are dealing with this problem by resorting to an adaptation of query rewriting techniques. We choose to express fine-grained access control through authorization views.