The National Library of Medicine announces its adoption of the Anglo-American standard for the formulation of journal title abbreviations according to the American National Standard for the Abbreviation of Titles of Periodicals (1969), with individual words abbreviated, in turn, according to the International List of Periodical Title Word Abbreviations (1970). The history of the activity of the specific Z39 Committee of USASI (now ANSI) concerned with journal title abbreviations is reviewed, covering the period from 1962 to the present. A history of the National Clearinghouse for Periodical Title Word Abbreviations and of the International List is also given. Former NLM usage is compared with the forms of the present International List and examples show the major changes in NLM abbreviations. The NLM Rules for Abbreviation of Periodical Titles as derived from the new standard are appended.