The prevalence of combined classroom classes in school, in comparison to usual classroom classes, is small and such form of work has not been frequently investigated. Combined classroom classes include a class consisting of two or more classrooms simultaneously taught by one teacher. Given the increased demands for the organization of teaching itself and the coordination of methods and forms to students of different age groups, the correlation and integration of multi-grade teaching material as well as individualization and differentiation occurs more frequently than in usual classroom classes. In the classroom environment, special attention is given to the creation of a positive classroom atmosphere. The research through participatory observation conducted in the two district schools in Sveti Ivan Zelina, where teaching takes place in the combined classes, teaching is analysed in a combined classroom with an emphasis on the classroom atmosphere and the classroom environment. Additionally, teachers' attitudes towards preparation and teaching, with the focus on the benefits and advantages of working in a combined classroom were analysed through the interview and the swot analysis. It is concluded that, for the success of working in the combined classes, a teacher's organization and quality planning of teaching processes is of utmost importance along with the use of various methods and the importance of individualization. The improvement of learning in these classes is also influenced by the classroom atmosphere that, due to the small number of students, becomes more comfortable and positive.