Abstract: Temperate subhumid grasslands extend in the eastern part of South America. This region represents one of the most diverse, largest and less transformed grassland areas in the world. The grasslands occupy the vast and continuous plains of centraleastern Argentina, Uruguay and southern Brazil that surround the Río de la Plata estuary. For this reason, they are referred to as the Río de la Plata grasslands. These grasslands, despite its apparent physiognomic homogeneity, hold high diversity of species, having grasses as the dominant life form except for few scattered shrubs and trees, and show a year-round photosynthetic activity. In this article we describe structural and functional characteristics of the vegetation of the Río de la Plata grasslands. We give an overview on biogeography, ecosystem functioning and services, human appropriation of primary production, disturbances, land use change, biological invasions and conservation status.