The Database Information System of Geological Localities (DISGL) was developed within the framework of the internal grant project of Faculty of Mining and Geology at VŠB - Technical University of Ostrava (IGS 2101/541) and GAČR (project No. 105/05/P545). The system is composed of three parts. The most important part is IS (Information System), storing geological data from various fields of geology. Accept of differently detailed geological data, it contains information about type, character, extent and condition of the locality. Significant part of the database system is data on exact position of the locality in different coordinate systems. Integral parts of the database are cartographic data, information about approach route to the locality and information for the GPS navigation. The DISGL offers the web server service with the PHP (Personal Home Page) and MySql database support. For comprehensible and graphically transparent interpretation of three-dimensional data, the second part of the system - MapServer, developed at the university in Minnesota (University of Minnesota, USA), is used. System enables interactive searching localities according to the locality type, petrographic composition, mineralogical occurrences, structural pattern, localization, etc. Further, selected data about locality are automatically converted by the system to the format acceptable for work with PDA. PDA utilization together with the GPS navigation is ideal solving for searching locality in the terrain. On the other hand developed PDA-application enables to add new localities located according to GPS to the system, or edit data about localities stored in database. Important data, which have been changing during the time (for example condition of the locality), can be edited easily. Functionality of the whole system is directly dependent on filling database with verified data. Sufficiently filled database helps to save time not only at searching information on geological localities, but also at searching the localities in terrain. The system facilitates field works or field trip planning.