Soil is one of the most important natural compartments supporting the maintenance of life. Soil delivers services through its functions: (1) food and other biomass production, (2) storing, filtering and transformation of materials, (3) habitat and gene pool of living organisms, (4) physical and cultural environment for humankind and, (5) source of raw materials. The ability of soil to perform any of these functions (on given levels) depends on its physical, biological and chemical attributes („internal” attributes), while the realization of the performance is conditioned by natural (e.g. slope steepness) and/or anthropogenic (e.g. drainage) factors ('external' factors). (All factors are time dependant) Humans, amongst the most influential players, indirectly alter the performance characteristics of soils, thus limit or enhance its capacity to function. The soil thematic strategy in the European Union (COM(2002)179) declares that for sustainable development, soils (soil functions) need to be protected from degradation. Main threats to soils are identified as decline in organic matter, soil erosion, compaction, salinisation, floods, landslides, contamination and sealing. The status of these parameters and the risk of their negative effect is in the central concept of the applied Soil Quality (SQ) approach (the thematic strategy) in Europe. Assessment of soil quality by this way allows for recognizing that the relative importance of soil functions are both spatially and temporally variable. In order to provide a framework to soil quality definitions, soil functions and major influencing factors have been reviewed. The term "Soil Functional Diversity" (SFD) is proposed to describe the number of different functions a soil can perform, recognizing the fact, that all functions are not equal. (Weighting of the importance of distinguished soil functions in special cases may be a valid option, taken local preferences or potentials into account.) Matching major threats and soil (and land) characteristics with regards to soil functions is the tool to evaluate Soil Functional Diversity and its stability. Consequently rather than a single universal expression of soil quality that characterizes the 'goodness' of soil, the conceptual approach in Europe allows for the implication of different quality perceptions for a wide range of applications (including economic analyses on a common bases of measurable parameters). Thus can support the synergies between local soil use options and regulative (CAP, international conventions etc.) conditions.