The aim of the study was to determine the efficacy of the entomopathogenic nematodes Steinernema feltiae and Steinernema carpocapsae applied to the overwintering generation of Colorado potato beetle (CPB). The nematodes were applied in three doses (4.5 mil./6 m2, 3.0 mil./6 m2 and 1.5 mil./6 m2) by watering the soil of a field where potatoes were grown in the past year. The CPB abundance and dynamics of emergence were monitored over a month in entomological cages. In total, majority (23.2%) of the CPB were collected on control, followed by the highest dose of S. feltiae and the medium dose of S. carpocapsae (19.2%), while the lowest numbers were recorded on the medium dose of S. feltiae (7.1%) and the lowest dose of S. carpocapsae (8.1%). The emergence of overwintered CPB was recorded on 6 April 2019 on the lowest dose of S. feltiae, the highest dose of S. carpocapsae and control, while on the other variants it was recorded on 10 April and 14 April 2019. The highest efficacy (69.57%) in suppressing the overwintering generation of Colorado potato beetles was achieved by applying the recommended (medium) dose of S. feltiae. Other variants showed significantly lower efficacy (17.39% to 65.22%). Given the results and favorable ecotoxicological profile, entomopathogenic nematodes have great potential in the biological control of Colorado potato beetle, which may contribute to slow the development of resistance of this important potato pest.