The main objective of this article is to present a sample lesson, which incorporates authentic materials, for the English course LM-1230 Oral Communication I based on the pedagogical principles of Content-based Instruction (CBI). This sample lesson will help novice instructors who will eventually teach Content-based Instruction courses at an intermediate level of English. The target population of this sample lesson and its sample tasks consists of students who take the second-year oral course of the English Major in the School of Modern Languages at the University of Costa Rica. Throughout this course, students cover two main topics: health issues and environmental problems.