Content Language and Integrated Learning (CLIL) refers to educational setting where a language other than the students’ mother tongue is used as a medium of instruction (Dalton-Puffer, 2007:1). CLIL has attracted a great interest in Indonesia since the implementation of RSBI (Rintisan Sekolah Bertaraf Internasional) or Pioneering International Standard Schools. One of the curriculum structures of RSBI is to use English as the media of instruction in teaching English, Math, Science and Technology, and for communicating out side the class. This book attempts to provide some practices of the implementation of the CLIL in teaching English which is integrated with Science as an approach to motivate the students to learn both content and language, especially in exposition writing. The teaching and learning process in exposition writing, the development of students’ ability in writing an exposition text, and challenges in the teaching and learning process at CLIL class will be discussed comprehensively. The book can be used as a practical and theoretical guide for teachers to expand their knowledge for considerations of teaching expository writing at CLIL class.