||Determining a nitrogen budget (inputs, outputs, and internal fluxes of nitrogen) for switchgrass can improve management and lower production costs. The objectives of this research were to study the nitrogen budget of switchgrass stands and to estimate their nitrogen use efficiency. The study was conducted on two well-established Cave-in-rock switchgrass stands in the Piedmont and Ridge and Valley regions of Virginia. Treatments of 9, 90, 180, and 270 kg N ha-1 were applied in May 2001. Shoot, root, and soil samples were collected in July, September, and November. Nitrogen applications did not increase yields on either site. Averaged across sites, yields of 10.5, 11.4, 11.6, and 11.6 Mg ha-1 were observed with rates of 0, 90, 180, and 270 kg N ha-1. Higher yields were observed at the ridge and valley site, where higher soil carbon and nitrogen were observed at the Piedmont site. Nitrogen was translocated from shoots to roots between September and November. Shoot and root nitrogen concentrations-but not yield-increased with increased nitrogen applied, i.e., there appeared to be luxury consumption of nitrogen. These data suggest switchgrass biomass production can be maximized with relatively low levels of applied nitrogen.