This thesis provides a general view of Bt-corn and the growing of this genetically modified plant in the Czech Republic. It comprises of two main parts, a theoretical and a practical one. The theoretical part deals with Bt-corn growing by agricultural companies and research institutes in the Czech Republic. The practical part provides a direct comparison of genetically modified and genetically unmodified corn. The DKC 3511 and DKC 4442 YG hybrids were selected as subjects of this comparison. The key aspects of the comparison are the outcrop and the extent of infestation of corncrops with fungic pathogens. Based on the results gathered in the practical and theoretical part of the thesis, pros and cons of Bt-corn growing in the Czech Republic will be assessed.