The floristic composition and vegetation partitioning of the ephemeral wetlands of the Pilliga Outwash within the Pilliga National Park and Pilliga State Conservation Area (30˚30'S, 149˚22'E) on the North Western Plains of New South Wales are described. SPOT5 imagery was used to map 340 wetlands across the Pilliga Out wash. A total of 240 plots within 31 wetlands explored composition and species richness in relation to water depth and wetland size. The predominant community described is the species-rich herb field of shallow basin wetlands, along with the structurally distinct but the less common sedge land/herb field of the deeper 'tank' wetlands and a single wetland with a floristically depauperate 'Diplachne fusca' wet grassland. A total of 131 taxa were recorded including three species listed under the NSW Threatened Species Conservation Act (1995): 'Eriocaulon australasicum', 'Lepidium monoplocoides' and 'Myriophyllum implicatum'. New records for an additional six taxa were recorded for the North Western Plains. 11% of taxa were exotic in origin.