The goal of the Oregon Intellectual Freedom Clearinghouse is to uphold the principles of the Library Bill of Rights in all types of libraries by improving communication between librarians, board members, professional associations, and other concerned groups in Oregon about challenges to intellectual freedom, and by increasing awareness as to how threats to intellectual freedom can be overcome. The data collection is limited to formal challenges to any type of library material in any type of Oregon library. A formal challenge is defined as a written "Request for Reconsideration" or "Statement of Concern" submitted by a group or individual to a library. Additional information is obtained from newspaper reports, if available. In a few instances, newspaper articles are the sole source of information about a challenge. This Thirteenth Annual Report on the Oregon Intellectual Freedom Clearinghouse summarizes 32 challenges against library materials that took place between July 1, 1999 and June 30, 2000. Twenty-four of the challenged titles were books, 6 were videotapes or DVDs, one was an audiotape, and one was an audiotape/book combination. Public libraries experienced 31 of the challenges and school libraries reported one challenge. Thirteen of the challenged items were designated as children's or young adult materials, and 19 were materials for adults. In 32 of the challenges, library staff committees or a school board decided that the materials should be retained. Three of those items were reclassified, one from children to adult, and to more accurately reflect the content in two cases. For each item listed, a summary of objections and a summary of events are provided. A statistical snapshot of the challenges reported since the inception of the Clearinghouse in May 1987 is then presented, followed by a 5-year overview of Clearinghouse data that analyzes the data in a graphic format. A final section identifies other intellectual freedom issues in Oregon in 1999-2000. (AEF)