Teachers play role models for children, therefore they can influence the formation of children's opinions. In the contemporary society, opinions of mathematics as something difficult and reserved for those talented in it still prevail. Considering that teachers can greatly influence children, the aim of this thesis is to present opinions and levels of mathematical knowledge in teachers, which are basis for their influence on children's learning and the formation of various opinions. This thesis consists of two separate parts: theoretical and research. The theoretical part is concerned with the coverage of formal mathematical education of primary school teachers and professors of mathemathics. However, the main focus of the theoretical part is concerned with Shulman's division of levels, or categories, of mathematical knowledge in teachers. The aim was to represent the two basic categories with their corresponding subcategories of knowledge. The basis of this thesis is the research which is concerned with the differences in mathematical knowledge between primary school teachers and professors of mathematics. By analyzing and interpreting the results of the research, one can conclude that there are differences between mathemathical knowledge of primary school teachers and professors of mathematics. The results are represented in the form of tables and values, calculated using the „Statistica“ programme, in order to infer whether there are statistically significant differences between the two groups of respondents.