With the development and massive use of digital media and processing technologies increases the dependence of information in digital format in organisms of the state administration, universities, libraries, companies and in general form in any institution is public or of the private sector. In the present research the main conceptual elements of the digital preservation are studied, the vulnerabilities and threats faced by digital documents. It describes a set of strategies that can be applied to safeguard the national bibliographic heritage. Finally, a proposal is made of the systems most used to guarantee the long-term preservation of information in digital format.