This article investigates one aspect of scientific style in French: the use of tenses. It investigates the claims made in the literature that the verb system of scientific French is a temporal. The frequency of tensed finite forms in 10 French language journal articles on biological sciences is examined. The rhetorical function of past and future tenses is examined and six functions of tense choice are isolated. This analysis suggests that tense marking is actually more complex than previous claims have maintained and that tense choice serves to encode (a) temporal, (b) rhetorical, and (c) structural processes in the scientific text. Tense choice is therefore part of the communicative repertoire of the scientific writer, which writers use to create and communicate information, and which is responsive to the rhetorical demands of communicating about science.