There is growing awareness of the impact health technologies can have on the environment and the negative consequences of these environmental impacts on human health. However, health system decision-makers may lack the expertise, data, or resources to incorporate environmental considerations when making decisions about the adoption and use of health technologies. In this article, we describe how health technology assessment (HTA) is evolving to address climate change by providing health system decision-makers with the information they can use to reduce the impact of health care systems on the environment. Our objective is to consider approaches for including the environment domain when conducting an HTA-in particular, the use of the deliberative process-and for determining when the domain should be included. We explore the challenges of gathering the relevant data necessary to assess the environmental impact of a health technology, and we describe a "triage" approach for determining when an in-depth environmental impact assessment is warranted. We also summarize related initiatives from HTA agencies around the world.