Cabbage seed weevil (Ceutorhynchus assimilis Payk.) is one of the most important and dangerous pests of oilseed rape in Poland and in other European countries. In contrast to another important oilseed rape insect pest – pollen beetle (Meligethes aeneus F.), little is known about cabbage seed weevil susceptibility level to insecticide active ingredients. Therefore, the aim of this study was to determine the cabbage seed weevil susceptibility to active ingredients from different insecticide groups. Research, carried out in 2015, 2016 and 2017 revealed very high susceptibility of the pest to organophosphates and all pyrethroid active ingredients, except for tau-fluvalinate, lower susceptibility to thiacloprid and very high resistance to indoxacarb from oxadiazines. This information is a basic element for creating integrated pest management strategies for oilseed rape in Poland.