Corn stover has great potential as a biomass feedstock due its widespread availability. However, storage characteristics of moist corn stover harvested from single-pass harvesters have not been well quantified. In 2007, moist whole-plant corn stover at 19.1 to 40.3 % (w.b.) moisture content was stored for 237 days in aerobic piles, one covered and one uncovered, as well an anaerobic silo bag. In 2008, two moist stover materials – whole-plant and cob/husk from 31.7 to 58.1% (w.b.) moisture - were stored for 183 or 204 days in covered and uncovered anaerobic piles, ventilated bags, or anaerobic silo bags. Stover stored in uncovered piles was rehydrated from precipitation, which increased biological activity and produced DM losses from 8.2% to 39.1% with an average of 21.5%. Stover in covered piles was successfully conserved when the average moisture was less than 25% (w.b.) with DM losses of 3.3%. Stover above 36% (w.b.) and piled under a plastic cover had DM losses from 6.4% to 20.2% with an average of 11.9%. Localized heating to temperatures where spontaneous combustion might be a concern (i.e. > 70°C) occurred in the aerobic piles when moisture was above 45% (w.b.). Ambient air blown through a center tube in the ventilated bag dried stover near the tube to an average of 24.2% (w.b.), but the remainder of the bag averaged 46.8% (w.b.) at removal. Loss of DM ranged from 7.4% to 22.0% with an average of 11.8%. Stover was most successfully conserved in the bags where anaerobic conditions were maintained. Under anaerobic conditions DM losses ranged from 0.2% to 0.9%. When anaerobic conditions were not maintained in the silo bag DM losses averaged 6.1% of DM. Anaerobic storage is the best solution for conserving the value of moist corn stover.