Teachers' professional development is an essential part of their work and personal growth in the field of education. Continuous professional training, with which the teachers develop their general educational and subject-specific competencies, is one of the main factors in this development. In the field of natural science teaching we often use the expression “natural science literacy” as a common word within all competences, because it represents the individual's ability to think and act scientifically in every life situation. One of the informal ways of teachers' professional training, by which teachers develop their competencies, is reading professional literature. Research has shown that teachers for their professional development mainly read popular science and general educational magazines, while they read professional science journals to a lesser extent. For reading professional journals and magazines teachers on average spend 2 to 4 hours per month, and they most often read at home in their free time. Reading professional journals is one of the most common forms of supplementary training for primary teachers in Slovenia.