A variety of methods were developed to measure soil biological activity. All these methods are not suited to produce generally accepted results, but they give relative information about the ecological status of soil. Soil enzymatic activity assays is only one way to measure the ecosystem status of soils. The technique is quite simple and produces reproducible results, and is nowadays of practical importance because the influence of agro-chemicals, industrial waste, heavy metals, as well as soil fertility management can be measured. Especially the search for urease inhibitor is of particular interest in order to reduce ammonia losses from soils. Soil enzymes have been reported as useful soil quality indicators due to their relationship to soil biology, being operationally practical, sensitive, integrative, ease to measure and described as "biological fingerprints" of past soil management, and relate to soil tillage and structure. The focus of this article is to provide a review of soil enzyme activity as a biological, process-level indicator for impacts of natural and anthropogenic activities on soils. This knowledge of soil enzymology can be applicable as bioindicator to human endeavour of ecosystem perturbation, agricultural practices and xenobiotic pollution.