In a Grid infrastructure, users submit job descriptions, specifying the requirements of their applications, to the Grid middleware in charge of finding and allocationg the appropriate computation and storage resources, by the process of matchmaking. Users may specify their requirements in terms of such resource attributes as, for example, CPU power, storage space, or software environment. In this paper we propose a simple middleware service, called a Dependability adapter, that enables users to specify requirements on resource dependability. Availability records are used to assess dependability, but the adapter’s mechanism could rely on other dependability metrics. The Dependability adapter relies on the already existing Grid services for matchmaking and service monitoring.