This article looks at the characteristics of Content-Based Instruction (CBI) and Content and Language Integrated Learning (CLIL) in order to examine their similarities and differences. The analysis shows that CBI/CLIL programmes share the same essential properties and are not pedagogically different from each other. In fact, the use of an L2 as the medium of instruction, the language, societal and educational aims and the typical type of child are the same in CBI and CLIL programmes. The use of both CBI and CLIL refers to programmes where academic content is taught through a second or additional language and the preference for one term over the other is associated with contextual and accidental characteristics. In this article, there are examples from Basque education where academic content is often taught through the medium of Basque and English to students with Spanish as a first language. The examples show that even if there are more subjects taught through the medium of Basque than through the medium of English, there are no essential differences between CBI (partial immersion in the Basque example) and CLIL (English-medium instruction in the Basque example). The need to share the research findings of CBI/CLIL programmes is highlighted.