Content-based instruction (CBI) is not a new term for foreign language teachers. By some accounts, CBI has been employed since the ancient Akkadians adopted Sumerian as the medium of instruction to educate their young in science and religion (Mehisto, Frigols, and Marsh 2008, 9). In the modern era, content-based approaches to language instruction have been employed in various forms since at least the 1960s, when Canadian language educators began teaching academic content in French to English mother-tongue children (Stoller 2008). Yet a large proportion of today's teachers of English as a Foreign Language (EFL) have never had the opportunity to try out CBI in their own classrooms--and many of these teachers may lack key professional knowledge and skills that are critical to successful CBI teaching. The purpose of this article is to consider ways that language-teacher education programs can better prepare future CBI teachers. After providing a brief rationale for why CBI approaches are particularly relevant in the 21st century, the author considers the competencies and skills that the language teachers of tomorrow will need to effectively integrate content and language instruction in their courses.