The International Standard Classification of Education (ISCED) was developed by the United Nations Educational, Scientific, and Cultural Organization in the 1960s and 1970s to be the recognized international standard for reporting and interpreting education program data. Creating a U.S. crosswalk to this system has been a goal of research conducted by the Office of Educational Research and Improvement that awaited the revision of the Classification of Instructional Programs (CIP) system. This publication contains a detailed discussion of the correspondence between U.S. education program databases and classification systems and the ISCED. It includes a crosswalk between ISCED and the 1990 CIP, and crosswalks between the ISCED and educational level classifications used in the Integrated Postsecondary Education Data System (IPEDS) and the Common Core of Data Survey (CCD), which collects data on primary and secondary education. The "Guide" also presents useful information on U.S. education program data. Technological and methodological considerations are discussed, and crosswalking data at various education levels are considered. An appendix of nearly 100 pages contains the master crosswalk of U.S. and ISCED codes. (SLD)