This work describes the structural characterization of hemicellulose isolated from hydroponically grown switchgrass in H2O medium (protiated) or 50% D2O medium (deuterated) through compositional analysis, GPC, FTIR, C-13 and H-1/C-13 HSQC NMR. 4-O-methyl glucuronoarabinoxylan (GAX), the major hemicellulose in switchgrass isolated from deuterated switchgrass, had structural properties similar to hemicellulose isolated from protiated switchgrass. Both had comparable arabinose to xylose ratio (0.25) and molecular weight (47-50 kDa). Structural similarities show that deuterated switchgrass hemicellulose can be used as a model carbohydrate polymer in neutron scattering, or pharmaceutical studies due to their immunomodulatory activity and gastroprotective effects.