Since 2009, the Gymnasium auf der Karhause has been offering a bilingual branch not only offering subjects from the field of social science but also Mathematics, Chemistry and Biology. This extraordinary profile offers an intensive bilingual education to our students, but is also a challenge to our teachers. Since there are no textbooks in bilingual Mathematics, the teachers have to be very creative in developing their own material and didactical approaches. In order to ease this burden on the teachers and to make sure that the classroom language and the material used in class are authentic and correct, the Gymnasium auf der Karthause would like to send its two bilingual Mathematic teachers to the vocational course “CLIL – Content an Language Integrated Learning” held by the International Study Programmes in Cheltenham/England in October. We chose this vocational training since we did not find any comparable teachers' training in Germany. Both of our teachers are highly experienced in bilingual teaching and they are both qualified to teach bilingual lessons. Moreover, Ms Caesar dealt with problems of the bilingual classes in both her theses and is constantly teaching and discussing current didactics with students from university. Ms Geisbe has been the coordinator of the bilingual branch since 2009 and is therefore not only interested in topics of didactics but also of school development. During the vocational training, both teachers will discuss didactical and methodical characteristics of bilingual education, intensify their own language skills, examine textbooks and exchange their knowledge and share their experiences on teaching bilingual classes with participants from other countries. Additionally, didactic approaches concerning maths and science classes used in Great Britain and topics of regional studies will be of importance in the vocational training, which will also improve intercultural competences. Therefore, part of the course content will be visiting a local school. Aspired goals of the training are on the one hand increased professionalism in the two teachers, which will enable them to teach bilingual lessons also in the Upper Secondary and which will motivate their students, on the other hand will they be able to spread the acquired knowledge concerning language and intercultural aspects among other bilingual teachers and university students in order to enhance the concept of bilingual classes in general.