Health impact assessment is a predictive tool to support decisions in policy-making. Current experience shows that health impact assessment could play an important role in the development of the Health in All Policies strategy. This strategy has been extensively used in other European countries and in a wide range of policy and administrative sectors. Health impact assessment is hardly ever mandatory and is frequently carried out separately from other impact assessments. The use of this process in Spain is relatively new, limited and fundamentally based on local level experiences and the screening of regional interventions. The current normative and organizational reform of public health in Spain provides an excellent opportunity to promote the development of health impact assessment. Some of the barriers to the development of this process are related to the biomedical model of health prevailing among health professionals, politicians, and the general population, political disaffection, lack of assessment culture, underdevelopment of community participation processes, and insufficient intersectoral work. Health impact assessment provides an opportunity to move toward improving the population’s health and reducing inequalities in health. Consequently, political commitment, as well as investment in education and research, is needed to introduce and develop health impact assessment in all administrative settings and policy sectors.