The aim of this Masters Thesis is to explore teachers perspective on the benefits and challenges of content and language integrated learning (CLIL). The implementation of content and language integrated learning (CLIL) triggers significant changes in the specific educational context and creates challenges for teachers working with CLIL as it introduces a new type of teaching. The study, conducted in a private high school in Rijeka, provides insights into teachers experiences in CLIL in relation to materials, support, teacher training, the role of L1, assessment and students. The data for this study have been collected by means of semi-structured interviews conducted with eight CLIL teachers. The findings suggest that CLIL poses more difficulties to the teachers than provides benefits to them. The major challenges identified by the teachers are related to difficulties finding materials, correlating the curriculum with the National Curriculum Framework and assessing students. Data also revealed differences between subject and language teachers with respect to the challenges they encounter. The study shows that teachers need more support, and a successful implementation of CLIL requires deeper coordination and cooperation among teachers, learners and CLIL stakeholders.