Prioritisation of assessment topics is an essential activity within HTA. Failure to successfully identify technologies that are likely to have the greatest impact on the health system carries an opportunity cost that is measured in poorer decision making, reduced patient benefits and less efficient use of public resources. Within individual agencies, prioritisation is also a business function that must balance the need to plan for and manage the allocation of resources with the need to provide expeditious advice to decision makers and adapt quickly to changing circumstances. This research describes a transparent and responsive framework for selecting health technologies to assess, minimising the potential for important technologies to be missed and providing a useful resource for HTA agencies facing similar issues. Topics are identified through a mix of routine horizon scanning, a formally convened advisory group consisting of the major decision makers from within the publicly funded health system and informal business intelligence gathering. Screening is carried out to eliminate technologies that are clearly unsuitable and provisionally grade all remaining candidates according to three principal criteria; 1) clinical impact (patient population, potential incremental effect and availability of alternatives); 2) economic impact (incremental costs and potential disruptive effect on how services are currently organised) and 3) policy impact (link to decision-making and factors that make it likely to feature on the national healthcare agenda). The screening process feeds into an in-depth expert group discussion, which also considers operational issues such as the extent of the advice required to inform the decision, data availability and costs associated with the assessment. We also describe a software visualisation tool developed to facilitate the prioritisation process, as well as measures for quality assurance and ongoing performance evaluation.