The purpose of this article is to review the status of Health Impact Assessment (HIA) in Switzerland and assess whether HIA can be used to implement Health in All Policies (HiAP) in this highly decentralized country. The methods include expert opinion and an extensive literature review, as well as targeted interviews with key informers in the cantons of Geneva, Jura and Ticino. HIA has been implemented successfully since the early 2000s in Switzerland. However, integration has been heterogeneous with only a few cantons taking the lead. Integration of HIA at the federal level was attempted in 2012 but failed due to resistance from a pro-business lobby. HIA in Switzerland has the potential to contribute to HiAP, but success depends on a wider dissemination of HIA and on some form of integration at the national level. In this respect, a‘bottom-up' approach based on inter-cantonal collaborations appearsmore promising than the‘top-down'federal level approach.