Health impact assessment (HIA) rests on a broader definition of health and integrates the social determinants of health into the elaboration of public policy. This short document introduces the reader to the main characteristics of HIA such as its definition, its rationale and principles, as well as its origins. The documents concludes with a brief presentation on the mandate and the vision of the NCCHPP regarding HIA, considered by the Centre to be an effective strategy for acting on healthy public policies.