It is in the interest of scholarly journals to publish important research and of researchers to publish in important journals. One key to making the case for the importance of research in a scholarly article is to incorporate value arguments. Yet there has been no rhetorical analysis of value arguments in the literature. In the context of rhetorical situation, stasis theory, and Swales's linguistic analysis of moves in introductions, this article examines value arguments in introductions of science research articles. Employing a corpus of 60 articles from three science journals, the author analyzes value arguments based on Toulmin's definition of argument and identifies three classes of value arguments and seven functions of these arguments in introductions. This analysis illuminates the rhetorical construction of value in science articles and provides a foundation for the empirical study of value in scholarship.