Assemblages of epigeic ground beetles living in spruce forests in three age ranges: 20-30 years (A); 40-50 years (B); 70-80 years (C) were submitted for research. The investigations were carried out in spruce forests in north-eastern Poland. In each age forest category, 4 plots with 5 Barber traps were set up. Ground beetle assemblages were compared in terms of their abundance, species richness, and the Shannon H’ Index value. Quantitative ecological description of carabids captured in the analysed age-classes of spruce forests was performed, and the values of the MIB (mean individual biomass) were calculated. To determine the dependencies between the values of the MIB and abundance of Carabidae trophic groups, the Spearman rank correlation coefficient was calculated. The assemblages of ground beetles living in the spruce forests in north-eastern Poland were characterised by quite large species richness. Significant differences were determined in the number of species richness between the Carabidae assemblages inhabiting the analysed age ranges of spruce forests. The oldest spruce stands had a smaller number of species and specimens of ground beetles as well as the highest MIB values in comparison with the younger spruce forests (30 to 50 years old). It was found that high MIB values were positively correlated with the presence of large ground beetle species with higher moisture requirements. Lower values of the MIB index were due to the presence of smaller, macropterous species, with the spring type of breeding and associated with open areas.