This Diploma Thesis deals with anglicisms and their frequency in the contemporary Czech language. It is primarily focused on the modern expressions. Diploma Thesis theoretical part covers general information about language, enriching of the lexicon and it compares Czech language with English. The practical part is divided into two self-contained sections. The first one presents and describes anglicisms which were excerpted from respectable Czech journals. These words are arranged into thematic groups according to the spheres of our life in which the influx of English terms is fairly evident. The following chapter provides the results of a questionnaire survey. The aim of the survey was to map the ability of common Czech speakers to understand the English expressions. It marginally touches their attitudes towards adaptation of words from English. The final part of the Project sums up the reached conclusions. The Diploma Thesis attachments contain the questionnaire and the graphs presenting the structure of respondents.