interventions implemented by governments are very frequently related to the determinants of health. health impact assessment (hia) is used as a predictive tool to include health in nonhealth policymaking. this paper defines hia, describes its methods, procedures and applications, and discusses opportunities and challenges associated with hia. doing a hia implies studying the intervention, profiling the target population, and estimating its impacts on health by means of combining quantitative and qualitative evidence. hia has been used in different kinds of policies (transports, urban regeneration, culture, energy development etc.), at different levels (local, national, european) and in many countries. despite its scarce use in spain, hia allows to consider health in sectorial policymaking, taking into account social inequalities in health, so that healthier public policies can be designed. on the other hand, hia is a tool under methodological development which use is hindered due to the existing narrow biomedical perspective on the determinants of health, and to the difficulties in working in public policy-making with multisectorial and participative perspectives.