The aboveground and the belowground biomass of Norway spruce and silver fir in a 60-year-old mixed fir-spruce stand were examined. Only very small interspecies differences in the weight and the dimensions of biomass distribution were found. Total dry weight of the biomass was 224.87 kg for fir (n = 5 individuals) and 229.60 kg for spruce (n = 5 individuals). Stemwood was the greatest component of total aboveground biomass of both fir and spruce, 74.01% and 78.33%, respectively. The proportion of belowground biomass in the total biomass of fir was 15.97% and for spruce 15.48%. Fir had a greater proportion of vertical roots and deeper root penetration (approximately by 20 cm) than spruce.