Recent standards and reform documents call for students to develop expertise in both disciplinary literacies and twenty-first century skills. Traditional perceptions of schooling focus on knowledge as a collection of facts and the role of teachers as disseminators of those facts, but such perceptions do not prepare students for today’s workforce (Sawyer, 2006). Very little of today’s jobs in the United States solely require knowledge of discrete facts or routine skills (Murnane & Levy, 2007). Instead, expertise has shifted from being able to memorize information to being able to find, make sense of and use information in a variety of contexts (Bransford, Brown & Cocking, 2000). One recent area of focus in the ELA Common Core State Standards (2012) and the Next Generation of Science Standards (May, 2012 draft) is the practice of argumentation. Specifically, in terms of history and science the ELA Common Core states that middle school students should be able to write discipline-specific arguments that “Introduce claim(s) about a topic or issue, acknowledge and distinguish the claim(s) from alternate or opposing claims, and organize the reasons and evidence logically.” (WHST.6-8.1). This professional development class will focus on how to support students in engaging in argumentation in both history and science using the claim, evidence and reasoning (CER) framework. Specifically, we will explore how evidence and reasoning are similar and different across history and science as well as how to provide appropriate scaffolds and instructional supports to help students gain greater expertise in argumentation in reading, writing and talking.