Perennial crops have fewer environmental impacts compared to annual crops, but there are no perennial grains available to replace the annual grains that occupy a majority of U.S. cropland. Here we report grain and biomass yields from an improved breeding population of intermediate wheatgrass (IWG) [Th i-nopyrum intermedium (Host) Buckworth & Dewey], a perennial grass being domesticated to serve as the first widely grown perennial grain crop. Our objective was to measure grain and biomass yields of this improved grain-type IWG (TLI-C2), a forage variety of IWG (cultivar Rush), and switchgrass (Pani-cum virgatum L.) in response to N fertilization rates ranging from 0 to 200 kg N ha–1. TLI-C2 grain yields responded qua-dratically to increasing N rates in all but one environment, but yields declined at high N rates due to lodging. TLI-C2 grain yields were highest during the first year of fertilization, yielding 961 and 893 kg ha–1 when fertilized at agronomically optimum nitrogen rates (AONRs) of 61 and 96 kg N ha–1 for stands seeded in fall of 2011 and spring of 2012, respectively. Grain yields declined with stand age. When fertilized with AONRs for grain, biomass yields of TLI-C2 harvested after grain ranged from 9.2 to 12.3 Mg ha–1 and had similar forage and bioenergy quality characteristics compared to Rush, which demonstrates the potential to manage TLI-C2 as a dual-use cropping system for both grain and forage.