Abstract The Colorado potato beetle (Leptinotarsa decemlineata) is probably the most dangerous pest species of potatoes. This study assessed the influence of expected climate warming on the number of Colorado potato beetle generations in the Wielkopolska region of Poland using two simulation models, SimLep 1 and NumoGen 1. Two types of data sets were utilised in the simulations: real meteorological data recorded in Winna Gora (52.2N; 17.4E) in the period 2002–2011 and virtual data obtained after transformation of the real data to include an increase in the recorded temperature values between 1 and 6°C. The threat to potato crops from Colorado potato beetle was found to increase in response to expected climate change. A temperature increase of 2°C above that recorded during the last few years would allow the development of two full generations of the beetle, and further temperature increases may even permit the occurrence of three generations.