The National Diet Library (NDL) is Japan's only national deposit library and also the country's parliamentary library. Timed with the opening of the Kansai-kan of the NDL in 2002, it has expanded its electronic library services. The NDL has been actively working on digitization of its collections. The “Digital Library from the Meiji Era” (http://kindai.ndl.go.jp/), which was opened to the public in 2002, carries full-text digital images of about 127,000 volumes of 89,000 titles of the books published in the Meiji era (1868-1912). In addition, it has been promoting copyright clearance and digitization of most of the books published in the Taisho era (1912-1926). The NDL offers the “NDL Gallery” (http://www.ndl.go.jp/en/gallery/index. html) as an online exhibition under the general title “Memories of Japan,” on specific themes, and introduces unique materials held by the NDL with descriptions and commentaries. Nine exhibitions are available so far, including the “Birth of the Constitution of Japan” and “Portraits of Modern Japanese Historical Figures.” We will sequentially add new contents. The “Web Archiving Project (WARP)” (http://warp.ndl.go.jp/) is a project to preserve information gathered from the Internet for the sake of future generations. We have collected selected Internet resources with license agreements, and provided about 1,500 online periodicals and 1,900 websites. These services are available to anyone via the NDL's website (http://www.ndl.go.jp/). Long-term digital preservation has become a significant issue. The NDL has conducted research on case examples of foreign countries and long-term preservation for packaged electronic publications since 2002. We will continue these studies to find practical application of migration and emulation. Based on the research results, the NDL has been working on construction of the NDL Digital Archive System which preserves and provides the digital information heritage of Japan for a long period. This system conforms to the Open Archival Information System (OAIS). We are also planning to construct a portal site for digital archives in Japan and are already providing the prototype (http://www.dap.ndl.go.jp/).