The aim of the research was developed in need to determine the level of environmental content (Environmental protection issues) in the didactic material of primary and secondary schools in the Republic of Serbia, as an important factor of the development of students’ environmental awareness. Mixed content analysis was used for the purpose of this study. This analysis included techniques for data collection. All textbooks and workbooks for primary and secondary school were used. The research showed that there is no equal distribution of questions about environmental protection within curricula and programs by classes and levels of education. Basically, didactic material includes about 5.4% of the content related to protection and preservation of the environment, which can influence the development of students’ environmental awareness.