Breclav - Pohansko is a fortress dating to the 9th century AD. Archaeological research at the site has been underway since 1958 and has uncovered a wealth of artefacts providing insight into Early Medieval society and culture. In 1995, Department of Archaeology first began applying GIS technology at the Breclav - Pohansko site. Since then, the researchers have digitised the archived excavation data, incorporated new information and initiated complex analysis projects with the GIS. In 2002 was published the fully digital catalogue of finds and terrain documentation, based on GIS technology. At the present day processing of the intra site spatial analysis by the using of the combination of GIS and multivariate statistics (PCA) continues. Geospatial technology enables not only to store and retrieve a variety of data types instantly, but also to spatially correlate relationships between artefacts and their discovered locations in the fort to better understand how tools and ceramics were used in daily life or rituals. The GIS was also used for archaeological predictive modelling in the neighbourhood area of fortress Breclav - Pohansko since 1999. It is a relatively new non-destructive method of archaeological research and study of the influence of landscape on distribution of archaeological sites. There is also possible to identify areas containing the unknown archaeological localities with help of archaeological predictive models. Models predicting the presence of seven types of archaeological sites were created for the near hinterland of fortress Breclav - Pohansko. These archaeological predictive models were produced on basis of Boolean layers in GIS and their outputs were maps showing three levels of potential presence of archaeological sites. These outputs were of relatively high quality.