Academic libraries see digital preservation as part of their fundamental mission to guarantee enduring access to the record of civilization?s accomplishments and discoveries. The nature of digital documents presents unique complications which challenge a library?s ability to assure long-term availability. Publishers view electronic backfiles as economic assets, and libraries do not control the physical object. Agreements between publishers and libraries require reaching an understanding on technical issues, the degree of access to the data held in a digital repository, and on the financial responsibility for preservation. This paper describes some of the efforts underway in the United States to establish standards for repositories and to implement digital archiving for electronic journals.