Health technology assessment (HTA) has over the past three decades become a well-established part of decisions about allocation of resources in many countries. Despite this, little is known about HTA's impact on health systems. Few studies have evaluated the benefits of HTA for health outcomes, for access to care or for public budgets. In contrast, HTA has relatively clear upfront costs, which could potentially discourage policy-makers from establishing HTA agencies, especially in low income countries with restricted resources. It may be premature, though, to dismiss this approach altogether, as less tangible modernizing goals are still significant.