Transforming biomass into a product with bulk density of 240 kg/m 3 (15 lb/ft3) would enhance logistics of truck transport to users throughout the year. We evaluated a system involving tub-grinding followed by roll-press compaction to increase the bulk density of biomass such as corn stover, corn cobs and native perennial grasses. Preliminary experiments were conducted to study the effect of particle size (tub-grinder screen sizes of 19.1, 76.2, and 203.2 mm) on the bulk density of roll-press compacted biomass materials. The bulk density of tub-ground biomass ranged from 50-100 kg/m 3 (3-6 lb/ft3). Tub-grinding followed by roll-press compaction increased the bulk density by two- to three-fold, and resulted in densified products with bulk density of 190-240 kg/m3 (12-15 lb/ft3). Additional increases in bulk density appear possible with improved design of the feeding system for the roll-press compaction machine.