The effect of the presence of microbial secreted exopolysaccharides (EPSs) on the hydraulic conductivity, water capture and moisture retaining capabilities of Induced Biological Soil Crusts (IBSCs) was investigated. In the experimental sites under study, located in Hobq Desert (China), the formation of these IBSCs was induced three to eight years before the tests by a massive inoculation in sandy soils of mixed cultures of Microcoleus vaginatus and Scytonema javanicum. In all the sites under study, the IBSCs showed to be well consolidated and differently developed in relation with their age. All the crust samples showed a significant content of EPSs, which contributed to the structure of the crusts. The hydraulic conductivity (HC) was significantly lower in the IBSCs than in the underlying bare soil and a statistically significant negative correlation between HC and the amount of high molecular weight (>100kDa; HMW) and of low molecular weight (