The mechanism of sulfate attack on portland cement concrete is not well understood. This has limited confidence that can be placed in and hence the reliability of existing standard tests and models to predict performance and service life of concrete subjected to sulfate attack. A systematic research effort is necessary to establish 5 criteria. This paper presents and discusses these 5 criteria. In addition, an approach for assessing the influence of pozzolans, or other cementing materials, on concrete performance and service life in sulfate environment is presented.