We present how resources and tools developed within the Human Language Technology Group at the University of Belgrade can be used for improvement of queries for the geodatabase within the Geological information system of Serbia (GeolISS). The first section of this paper introduces the approach to GeolISS development, whose main goal is the integration of existing geologic archives, data from published maps on different scales, newly acquired field data, Intranet and Internet publishing of geologic information. The Faculty of Mining and Geology of Belgrade University realized the GeolISS project financed by the Ministry of Environmental protection during the period 2004–2006, and from that time many institutions working with geologic data have been using GeolISS. In the second section implementation details are presented, while section 3 presents GeolISS search functionalities. Efficient exploration of such a valuable source of geologic data in view of the diversity and amount of archived data, which is of paramount importance for the quality of results obtained by the query, can be substantially improved by using various lexical resources, such as morphological dictionaries and a geological dictionary. These lexical resources used within WS4QE (Workstation for query expansion) enable semantic and morphological expansion of the query, the latter being very important in highly inflective languages, such as Serbian, which is outlined in section 4. Evaluation of query improvement is described in section 5.