This paper provides an overview of conservation status and major threats to grouse based on information collected by the IUCN/SSC BirdLife WPA Grouse Specialist Group during 2004-2005. At the time of compiling the first Grouse Action Plan (Storch 2000b) in 1999, no grouse species were considered to be threatened following the IUCN criteria, but three species with limited geographic distribution were listed as Near Threatened (IUCN 1996): Caucasian black grouse Tetrao mlokosiewiczi, Chinese grouse Bonasa sewerzowi, and Siberian grouse Dendragapus falcipennis. In 2000, the newly recognised Gunnison sage-grouse Centrocercus minimus was listed as Endangered and the Caucasian black grouse was reclassified to Data Deficient. Shortly after, both the lesser prairie-chicken Tympanuchus pallidinctus and the greater prairie-chicken T. cupido were added to the Red List as Vulnerable owing to rapid population declines, and the greater sage-grouse Centrocercus urophasianus was listed as Near Threatened (IUCN 2004). At a national level, 14 of the 18 known grouse species are red-listed in at least one country. Populations at the southern edge of a species' range and in densely populated regions are most often red-listed. Based on questionnaire responses from 47 countries, habitat degradation, loss and fragmentation due to human land use activities are the major threats to grouse viability. Exploitation, predation, human disturbance and climate change were regionally believed to be critical. Integrating habitat preservation and human land use practices is concluded to be the major challenge to grouse conservationists worldwide.