A huge amount of geographical datasets are becoming available in distributed environments like Spatial Data Infrastructures (SDI). These datasets are very heterogeneous since they come from different independent sources and surveys and are structured in different formats. In the context of a national SDI that needs to assure an adequate quality level of the data it provides, it is necessary to face the problem of data validation in an uniform way independently from the chosen implementation technology. In this paper we present the tools and methodology for data validation which have been developed to support the construction of the Italian SDI. These tools are conformant to the relevant ISO 19100 and Open Geospatial Consortium (OGC) standards.