The Hydrogeological Map of Mongolia, scale 1 : 1 million, was produced cooperatively by Mongolian and German hydrogeologists from 1993 to 1996. The map project was executed by the Mongolian Geological Survey and the German Geological Survey (Federal Institute for Geosciences and Natural Resources - BGR). It was financed by the Mongolian side from research funds of the Ministry of Education, Culture and Science, and on the German side by the Federal Ministry of Economic Cooperation and Development (BMZ). The objective of the project was to support the Mongolian partner institution in the preparation and production of the hydrogeological map at a scale of 1 : 1,000,000. The explanations for the Hydrogeological Map of Mongolia 1 : 1 000000 contain overviews on geology and hydrogeology, short information about orographic, climatic and hydrographic conditions, indications about compilation and content of the map as well as a bibliography.