Basic geological map of the Republic of Croatia scale 1:50,000 forms the second stage of production of basic geological map scale 1:100,000, which has a very wide application in science and the economy and sustainable development of the Republic of Croatia, and which was also created at the Department of geology of the Croatian Deological Survey. This ensured an uninterrupted sequence of systematic geological research for the purpose of more complete knowledge of the national territory and its natural resources and the development of geological science. Basic geological map of the Republic of Croatia scale 1:50,000 is methodologically based on the lithostratigraphic division of rocks and sediments near the surface, so as such it enables targeted research of potential mineral resources, and the separation of permeable from less permeable rocks during water research, a more objective assessment of geological hazards, and obtaining a better insight into the deep geological construction during the exploration of hydrocarbons and thermal energy. Knowledge of the geological structure is one of the basic prerequisites for the sustainable use of natural resources and spatial planning, i.e. the sustainable development of a region or country. Basic geological map of the Republic of Croatia forms the basis for all thematic geological maps and for research at the level of applied geology, whereby the interdisciplinary approach to creating thematic maps increases the transfer of knowledge within geological disciplines, but also between geologists and experts in other specialties (seismologists, spatial planners, landscape engineers, urban planners etc.).