The floristic composition of campo limpo úmido, a moist savanna grassland vegetation of the cerrado biome, is still little described, even though its herbs and subshrubs form a major component of the cerrado vegetation. The objective of this study was to characterize the floristic richness of the herbaceous and subshrub layer of a moist grassland at the Água Fria Farm, Alto Paraíso, Goiás State (14°04′8.83″S, 47°30′33.1″W). The principal use of such grasslands is to graze cattle; in addition, local people collect vast numbers of selected species of wild plants to sell for the decorative dried plant trade, or for their medicinal qualities. Little is known, however, about the sustainability of this extractivism. A survey of a 21 ha area, with intensive quarterly collections of herbarium specimens, was made from April 2000 to March 2001. Despite the small size of the study site it proved to be very rich floristically. A total of 207 species in 90 genera and 33 families was registered in the area. Thirty-one species not yet recorded in the checklist of the flora of the cerrado biome were found in this study, plus three that seem to be new to science. The richest families were Cyperaceae (30 species), Poaceae (28), Xyridaceae (23), Eriocaulaceae (20), Asteraceae (18), and Orchidaceae and Melastomataceae with 10 species each. These results suggest the need for more research on the moist grassland to provide overall estimates for the plant species richness of this widespread vegetation type and as a basis to help guide conservation and management policies.