The organization of a historical collection in a medical library presents many problems. Among these are space limitations, choice of material to be included, and classification. This paper discusses the organization of the historical collection particularly as it relates to books and journals in the Rudolph Matas Medical Library of Tulane University. The problem of classification is discussed at length. The principal classification systems are reviewed, particularly that of the National Library of Medicine Classification. The expansion of the NLM scheme to suit our purpose is presented. This includes classifying Americana imprints by subject rather than state, changing the termination date of Americana to 1900, grouping the history of specialties with books on the history of medicine, and recognizing the problem involved in reclassifying books on military medicine and surgery. The selection and arrangement of periodicals relating to the history of medicine is also discussed.