Health impact assessment (HIA) is a multidisciplinary tool aimed at assessing the effects of policies, programs and projects on health. It comprises five phases: screening, scoping, appraisal, reporting and monitoring. A review of the literature was performed on the subject which allowed us to describe good practices for each phase and show that the method is applied in a heterogeneous manner. Despite the correct application of the tool, especially of appraisal and reporting, the evaluation phase should be more widely used.