[영문]Such systems have been introduced in some countries during the past decade amid debate about how they should be organized, but there is no collated information about where they exist or how they work. This study was designed to provide hitherto unavailable information about the existence, organization, methods, and outputs of systems aimed at influencing the use of interventional procedures in different countries.Methods: Data were gathered from a questionnaire survey of key informers associated with healthcare technology assessment (HTA) organizations in different countries.Results: Responses were received from key informers working for twenty-eight HTA organizations in twenty-five countries (response rate 83 percent). Information about a national system for assessing interventional procedures was obtained for fifteen countries. There was substantial variability in the type and funding of these organizations, the systems used for the selection of procedures, the types and sources of evidence used, the personnel involved in the appraisal of the evidence, the arrangements for consultation on the draft assessment, the format of assessment recommendations, the status of the guidance, and the use of guidance from other countries.Conclusion: Guidance on interventional procedures is produced variably in different countries?and not at all in some. Greater international collaboration in the assessment of new interventional procedures could help to optimize the efficiency of existing systems as well as the quality of the assessments, by capitalizing on the outputs from scarce (international) resources and expertise.