Health Impact Assessment (HIA) can be defined as defining and predicting the health impacts of decisions under preparation, in order to ensure that the impacts are taking into consideration in the decision making. The thesis is about the short development history of HIA from an idea to the first round experience of putting it into practice. The articles of the thesis explore the need for HIA in preparing proposals for tyhe Swedish parliament, what kind of quantitative methodology would be appropriate for predicting impacts, how the already published scienticif HIA-reports have followed the principles of scientific rigorousness, participation, ethics and sustainable development set for assessments as well as the experience of HIA practice in Sweden ans Slovakia.

The main conclusion is that HIA works best whne it is apllied as a part of public health advocacy by health autorities or pulblic health non-governmental organizations. The challenge for HIA is its ambitious aim to create basis for evidence based policies, which would require solutions to the technical demands for creating scientific predictions. In practice, predicting health impacts comprehensively is not an easy task. The different sectors of public administration semm to have a postive attitude towards HIA, in principle. However, there seems to be many practical obstacles related to financing, administration and politics of public sectors.