CLIL (Content and Language Integrated Learning) has been one of the major innovations that has been implemented in Spain in the last decades and many questions have arisen in relation to its effectiveness. The aim of this article is to report primary teachers' perceptions of the most relevant aspects of CLIL teaching of Science and Social Science in Primary Education in the Region of Murcia. Their perceptions of this integrated approach are crucial to meet their needs, coordinate their efforts and develop good practice. Results from this research emphasize an extensive application of CLIL methodological guidelines and the use of a wide range of tools when evaluating learners' competences. Additionally, they have expressed their satisfaction with language assistants when motivating pupils and fostering their oral skills and intercultural awareness. However, CLIL teachers believe Public Administration should provide more resources, further training and enhanced coordination to improve the quality of education under this paradigm.