This article reports on a review and analysis of the role of strategic environmental assessment (SEA) and cumulative impact assessment (CIA) in the overall framework of environmental impact assessment (EIA). It is argued that to pursue the nationally agreed goal of ecologically sustainable development (ESD), it is essential to incorporate SEA and CIA into the EIA process. The article examines how SEA and CIA might be applied and addresses the implications. It notes that there are significant challenges in science, assessment technique and administration. Two specific areas of difficulty are highlighted, these being the lack of adequate information about environmental components and processes, and the likelihood of significant institutional impediments, both intergovernmental and within the bureaucracy. The discussion identifies approaches to assist in resolving these difficulties. The article concludes that, despite the challenges, SEA and CIA must be pursued, are “within our grasp now” and are critical for the pursuit of ESD.