ABSTRACT. Checklist of the birds of the state of Mato Grosso do Sul, Brazil. Contrasting with several other Brazilian states, just recently the state of Mato Grosso do Sul started to organize an inventory of its birdlife. We list 630 species of birds for the Mato Grosso do Sul, belonging to 26 orders and 74 families, representing 34% of birds occurring in Brazil. About 90% of these species have documented records of its occurrence in the state (Main List), according to proposed by CBRO. The others species still wait for adequate supporting documentation (Secondary List). Forty fi ve species were excluded for the Main List and included in Tertiary List due to problems in supporting documentation and/or incompatible distribution. The variety of landscapes and vegetation types under the infl uence of the biomes Cerrado, Pantanal, Atlantic forest, Chaco and Bosque Chiquitano is partly responsible for the high species diversity in Mato Grosso do Sul. However, several of these landscapes have been suppressed and/or severely altered by pastures, agriculture (mostly monocultures of sugar cane and soybeans) and agroforestry (Pinus and Eucalyptus). Thirty-eight species of birds occurring in the state were present on red lists at the global and/or national level. There are still large gaps in knowledge about the avifauna of Mato Grosso do Sul, mainly in the region of Paiaguás in the Pantanal wetlands and in neighboring regions with the state of Goiás, Paraguay (Chaco) and Bolivia (Bosque Chiquitano).