Objectives: The aim of the study is to make an international comparison of Health Technology Assessment (HTA) Agencies, to show their similarities and differences.

Methods: An e-mail questionnaire was sent to thirty HTA agencies internationally. Questions related to the structure of the agency, the relationship with health-related institutions, the prescriptiveness of the decisions taken, the main core and the modalities to spread the assessment, and the type of funding.

Results: Twenty-four HTA Agencies answered the questionnaire: 25 percent in America, 4.2 percent in Australia, and 70.8 percent in Europe. Fifty-four percent of HTA Agencies are governmental institutions (83.3 percent have central government funding), while 62.5 percent have relationships with health-related governmental institutions. Of the agencies, 87 percent reported that their decisions are not prescriptive, while for 20.8 percent and 8.3 percent of them stated that this was the case totally or partially, respectively, especially for the governmental and American Agencies. Seventeen agencies (70.8 percent) declared their work on multiannual programs (77 percent of the governmental HTA Agencies and 100 percent of the American ones). The assessments mainly addressed diagnostic procedures (85.7 percent) and pharmaceuticals (25 percent). The most common way to disseminate results is by means of paper report (91.7 percent), followed by the Internet (16.7 percent), and seminars to expert audiences (12.5 percent).

Conclusions: The comparative analysis of HTA Agencies showed that governmental and American Agencies have a profound impact on the prescriptiveness of their assessment, and this could be linked to the fact that these types of Agencies work on multiannual programs. European and American HTA Agencies have many similarities in terms of type of assessment, funding, and dissemination of results.