The bachelor thesis deals with the analysis of lexically-semantic level of children’s speech at preparatory class of primary school. The thesis is divided into two parts. Theoretical part includes two chapters and is based on analysis of specialized literature dealing with the given problems. First chapter pays attention to preparatory class, school maturity and the appropriate legislation. Second chapter defines the level of children’s development at age corresponding to preparatory class. It is also characterised speech according to individual language levels and speech impairment. There are described the kinds of speech impairment which appeared during research. In the research project there is worked out the analysis of lexically-semantic level of speech at preparatory class of primary school. The aim of the thesis was to find out the children’s level of passive and active vocabulary and their ability to form synonyms, antonyms and paramount terms. For picking up the information it was used the test of passive and active vocabulary and picture materials taken from the book named Školní zralost: co by mělo umět dítě před vstupem do školy, authors Bednářová a Šmardová (2010). The research project has got qualitative form with quantitative elements. The picked up information were worked out to charts completed with graphical illustration for lucidity.