This thesis is about a potential trade-off between integrity and long-term usability in the choice of file formats for preservation of text documents. Five common formats are discussed: plain text, PDF/A, Office Open XML Document, Open Document Text, and Markdown. The formats are compared with respect to four criteria related to integrity and usability and to the records continuum model: support by widely used software, stability, rendering of contents and reusability. It is concluded that no single format is optimal with respect to all four criteria, when it comes to preserving typical documents in a modern environment, with more or less complex formatting and document structure. Therefore, the feasiblity of using two or more formats for preservation of a single document (e.g. PDF/A combined with Markdown and/or Office Open XML) is discussed. It is necessary to weigh the importance of integrity and long-term usability against the costs of preserving documents in multiple formats. This is a two years master's thesis in Archival Science, Library and Museum studies.