This document specifies a method for the measurement of several hydrolase activities (arylamidase, arylsulfatase, ß-galactosidase, a-glucosidase, ß-glucosidase, N-acetyl-glucosaminidase, acid, alkaline and global phosphatases, urease) simultaneously (or not) in soil samples, using colorimetric substrates. Enzyme activities of soil vary seasonally and depend on soil chemical, physical and biological characteristics. This method can be applied either to detect harmful effects on soil enzyme activities derived from toxic substances or other anthropogenic agents in contaminated soils against a control soil, or to test chemicals.