It is with tremendous sadness that we report the passing, on 6 November 2008, of Ronald M. Davis, MD, past President of the American Medical Association (AMA) and a major supporter of the One Health Initiative. Indeed, the AMA wouldn't have passed its historic One Health Resolution without Ron's leadership. As the first preventive medicine physician to be president of the AMA, he recognised the need for collaboration between veterinarians and physicians. As he said, 'I was primed for the issue of One Health'. Roger Mahr, who was President of the AVMA at the same time, contacted Ron to discuss bringing animal and human medicine together. They met and had dinner together. After Roger educated Ron about the issues, Ron told him that he would be happy to help. Ron not only advocated One Health principles within AMA, but he personally represented AMA on the AVMA One Health Initiative Task Force and contributed materially to the development of the Task Force recommendations (www.avma.org/ onehealth/). This was a case where the right people were in the right place at the right time. In our subsequent One Health collaborations regarding drafting the AMA One Health Resolution and other related issues, Ron always graciously and expeditiously supported and guided our efforts with much wisdom. Tragically, not long after the AMA passed the One Health Resolution in June 2007, Ron was diagnosed with stage 4 pancreatic cancer. He fought the disease with grace and dignity. The New York Times reported on his battle. (www.nytimes.com/2008/09/23/health/23voic.html?partner=rssnyt&emc=rss). On 14 June 2008, at the AMA Annual Meeting of the House of Delegates, Ron gave a very moving speech entitled Legacies in the circle of life. The transcript can be read at www.ama-assn.org/ama/no-index/news-events/18670.shtml and the video can be watched at www.webguild.com/TeamRon/. The world has lost a great man and we have lost an esteemed colleague, friend, and One Health champion.