This article presents an empirical study about the students' perspectives on bilingual sections in Compulsory Secondary Education (CSE) in the Community of Madrid, Spain. Its aim is to highlight the students' opinions and their level of satisfaction of Content and Language Integrated Learning (CLIL) in this monolingual setting. The results extrapolate from the analysis of questionnaires and focus groups interviews. These two methods of research gave excellent opportunities for 754 bilingual participants in 18 bilingual schools (schools are public, charter, and private ones from both rural and urban areas) to expose their opinions and attitudes about the program. Thus, the article outlines the main findings in relation to the following factors: students' use, competence and development of English in class; methodology; materials and resources; evaluation; teachers' use, competence and development of English in class; mobility; improvement and motivation towards learning English; teacher training and mobility; and finally, overall appraisal of bilingual sections.