Background: Research on the presentation of information in narrative versus expository text genres is inconclusive with respect to the question of which is more beneficial for student learning. Aims: We examine the effect of presenting factual content in either narrative or expository genres on student learning. We also consider relevant prior knowledge and working memory capacity (WMC) as potential mediating variables. Sample: Ninety university undergraduate students. Methods: Subjects studied circulatory system content embedded in either narrative or expository texts. Prior circulatory system knowledge, knowledge improvement (learning) and free recall were assessed. Results: Learning and recall did not differ as a function of text genre overall, but did interact with prior knowledge. Learning from the narrative and one expository text was optimal at intermediate levels of prior knowledge, with higher knowledge readers benefiting more from the expository text compared with the narrative text. Prior knowledge was positively related to recall for the expository texts, but unrelated for the narrative text. Subjects' WMC did not predict learning or recall. Conclusions: Results suggest that narrative and expository processing differ with respect to integration of text content with prior knowledge.