To comply with their human rights legal obligations, governments should carry out human rights impact assessments prior to adopting and implementing policies. This article summarizes a larger report in which the authors outline a human rights impact assessment methodology, using the right to the highest attainable standard of health as a case study. The authors recommend a mainstreaming approach, which involves integrating human rights into existing impact assessment methodologies. In this article, the authors propose testing their mainstreaming approach by integrating the right to the highest attainable standard of health into existing health impact assessment.