We report use of an underground roost by an adult male evening bat (Nycticeius humeralis) during winter in southwestern Missouri. The bat was fitted with a radio-transmitter and followed to tree roosts for 28 days before it was found in a hole covered by leaf litter at the base of a live white oak tree (Quercus alba). The bat remained in the underground roost for 3 days that coincided with extremely cold ambient temperatures before moving back to a tree roost.