The Global Climate Observing System (GCOS) is approaching its 20th anniversary. Much progress has been made since its establishment in response to the urgent needs identified by the Second World Climate Conference in 1990 and a major stock-take of progress is now underway for report to the Conference of the Parties to the UN Framework Convention on Climate Change in mid-2009, as well as to World Climate Conference 3 in August-September 2009. Collaboration and cooperation have increased greatly across the main component observing systems of GCOS, including the Global Ocean Observing System (GOOS), the WMO Integrated Global Observing Systems (WIGOS) and the Global Terrestrial Observing System (GTOS) and GCOS itself is being developed as the climate observing component of the Global Earth Observation System of Systems (GEOSS). There are, however, very serious deficiencies in climate observing capabilities world-wide, as well as in the processing and use of GCOS data in support of the full range of user needs, including, especially, the international effort on planning for adaptation to climate change under the Nairobi Work Programme of the UNFCCC. In the light of information assembled for the 2009 Progress Report to the UNFCCC, the WMO (World Meteorological Organization)-IOC (Intergovernmental Oceanographic Commission)-UNEP (United Nations Environment Programme)-ICSU (International Council for Science) Steering Committee for GCOS is in the process of reviewing and revising the GCOS Strategy and Implementation Plan for consideration by the GCOS sponsors and other relevant international organizations. This presentation will provide a summary of the latest information on GCOS progress and plans.