A collection of papers presented at the 1st Kyoto International Symposium on Underground Environment entitled "Role of Geo-technology to the Underground Environment", held in Kyoto, Japan, from 17-18 March 2003. It consists of nine keynote papers, 31 technical papers and 15 papers resulting from the poster presentations. These papers are divided between the following categories: * rock fracture * contamination and barrier * groundwater * underground measurement * rock stability * GIS and geostatistics * seismic monitoring. These papers provide comprehensive solutions to the understanding of the underground environment.