The rendzinas were studied in the community of beech, fir and spruce with Scots pine (Piceo-Fago-Abietetum subass. pinetosum silvestris), at the altitudes above 1,000 m, on steep slopes and warm aspects. The genesis and properties of these rendzinas were strongly affected by chemical composition, mineralogical structure and bedrock weathering. Soft limestones, which are characterized by low hardness and a higher content of insoluble residue, present the major impact on the physical and chemical characteristics of rendzinas. The presence of active carbonates in the profile causes a neutral to weak alkaline reaction, provides the constant buffering of organic acids and the formation of Ca-humates, and in this way also the formation of a stable organic-mineral complex, which in turn results in the formation of stable grainy soil structure.