Objectives: The aim of this study was to present the first four collaborative health technology assessment (HTA) processes on health technologies of different types and life cycles targeted toward diverse HTA users and facilitators, as well as the barriers of these collaborations.

Methods: Retrospective analysis, through four case studies, was performed on the first four collaboration experiences of agencies participating in the EUnetHTA Joint Action project (2010–12), comprising different types and life cycles of health technologies for a diverse target audience, and different types of collaboration. The methods used to initiate collaboration, partner contributions, the assessment methodology, report structure, time frame, and factors acting as possible barriers to and facilitators of this collaboration were described.

Results: Two ways were used to initiate collaboration in the first four collaborative HTA processes: active brokering of information, so-called “calls for collaboration,” and individual contact between agencies after identifying a topic common to two agencies in the Planned and Ongoing Projects database. Several success factors are recognized: predefined project management, high degree of commitment to the project; adherence to timelines; high relevance of technology; a common understanding of the methods applied and advanced experience in HTA; finally, acceptance of English-written reports by decision makers in non–English-speaking countries. Barriers like late identification of collaborative partners, nonacceptance of English language and different methodology of assessment should be overcome.

Conclusions: Timely and efficient, different collaborative HTA processes on relative efficacy/effectiveness and safety on different types and life cycles of health technologies, targeted toward diverse HTA users in Europe are possible. There are still barriers to overcome.