The International Union of Geological Sciences (IUGS), founded in 1961. has developed into one of the strongest unions of the ICSU family. A composite but efficient international working structure has been organized, based on extensive voluntary efforts which are moderately yet effectively subsidized by the Union. Current developments trend towards closer cooperation with the International Geological Congress. The IUGS now covers 74 countries, although the strength in the international working structure may be contrasted with a certain lack of promotion at the national level, particularly with regard to information. This must be remedied. Geologists concerned are also encouraged to obtain their information directly through the IUGS Geological Newsletter.