In diploma thesis, primarily based on foreign sources, the development and causes of resistance of the pollen beetle (Meligethes aeneus [F.]) to synthetic insecticides is presented. In favorable conditions, the pest can cause significant economic damage to the oilseed rape (Brassica napus L. var. napus) and rape (Brassica rapa subsp. oleifera). Pollen beetle feeds with pollen. It damages only closed flowers while searching for pollen. Damage is seen as a little holes in the flower. In recent years, some countries in the European union have already noted the resistance to certain synthetic pyrethroids. There are specimens that transmit harmlessly to the concentrations of active substances, which work on most other specimens of the same species. The emergence of resistance is the selection process. It begins if there is only a small number of individuals in a population who have a heredity of a small sensitivity to an active substance and because of this reason they can survive suppression with this substance. In the case of repeated use of the preparations based on this active substance, next generations will begin to accumulate hereditary contepts for resistance. The later populations of specimens which are ressistant can be suppressed with very high concentrations of the active substance or can not be suppressed at all. In my work we tried to study the causes of resistance of pollen beetle and examine how the resistance process can be avoided or at least slowed.