Few academic genres have received more attention than the research abstract. Its increasing importance, diverse functions and convenient length mean it has been dismembered and dissected by analysts in countless articles. This is a key genre, central to researchers’ reading decisions and therefore to the creation of new knowledge, and as a result writers use a variety of interactive resources to attract readers to the accompanying article. Despite this interest, however, negation has largely escaped EAP scrutiny. This study, therefore, seeks to correct this oversight by examining negation in research abstracts and the extent it contributes to rhetorical persuasion. Drawing on a diachronic corpus of research abstracts, we show how negation contributes to an interpersonal model of academic writing and describe the forms, functions and distribution of negation across time and disciplines. The results not only add to our knowledge of the rhetorical functions of negation but also raise important pedagogical implication for English for Academic Purposes.