|Genetically modified (GM) Bt maize MON810 is promoted as being beneficial for farmers and the environment. The aim of this study was to compare particular claims of the benefits associated with this GM maize with Czech farmers' practice. Ten semi-structured interviews and 27 questionnaires obtained from Czech farmers who had grown Bt maize for at least one year in 2005–2016 were analysed qualitatively. The alleged benefits of MON810 cultivation regarding lower levels of fungal disease infestation, yield increase, reduction of insecticide usage, lowered costs, time saving and simple manipulation were enjoyed by a varying proportion of Czech GM farmers. In contrast, some farmers experienced the opposite of the claimed benefit regarding yield, costs, manipulation and time requirements. The exception was the 100% control of the European Corn Borer (ECB). The current and previous studies suggest that most of the benefits manifest themselves rather on farms under high ECB pressure. Seen from an economic viewpoint, the cultivation of Bt maize could be recommended in areas with persistent high corn borer pressure. However, the benefit to the environment is challenged and it is suggested that farmers should employ a complex of cultural control methods.