An emission inventory for volatile organic compounds (VOCs) emitted from biogenic sources has been developed for the Metropolitan Air Quality Study region (MAQSR) of NSW Australia (Fig. 1). The spatially and temporally varying inventory was developed based on a Geographic Information System (GIS), remote sensing data and field measurement data. The inventory has a spatial resolution of 1x1 km² and a time resolution of 1 hour. Urban, agricultural and natural land-use distributions in the MAQS region were combined with biomass factors for each land-use category to produce a spatially resolved biomass inventory. A biogenic emission inventory was then developed by combining the biomass inventory with hourly emission rates for trees, shrubs and cut and uncut grass species. Biogenic emission rates were measured for 19 native tree species representative of the region and 6 types of grass using an enclosure method. Real time measurements of isoprene and its oxidation products were made in several forested areas within the study region and compared to model predictions. Canopy and grass models, which take into account radiation, shading, temperature, biomass and leaf area index were developed based on the experimental results and recent literature values.