The first thematic guide to international archival collections relating to Dr. J. L. Todd (1876-1949) has been completed and is now available online at the Osler Library of the History of Medicine web site. J. L. Todd was Canada’s first professor of Parasitology and a noted pioneer on the subject. He was also involved with tropical medicine research in Africa, the Canadian Army Medical Corps, the development of the Canadian pension administration, and an investigation of Poland’s typhus outbreak in the 1920s. The guide consolidates holdings information about all known collections relating to Todd’s medical career as well as his personal papers and includes institutions in Canada, the United States, and England. It was prepared by researchers at McGill University’s Osler Library and Redpath Museum with support from Associated Medical Services Inc. (Toronto).