The first record of western yellow bat (Lasiurus xanthinus) for Nevada was found at the Moapa Valley National Wildlife Refuge, Muddy River, Clark County in January 1999. Year-round residence and an active breeding colony were verified through 2000. Roosting and foraging seems concentrated within extensive California fan palm groves throughout the upper Moapa Valley. Capture and acoustic sampling showed this to be the second-most abundant species in the valley. The diet included Coleoptera, Diptera, Hemiptera, Homoptera, Lepidoptera, and Orthoptera. This record represents the northernmost distribution of the species.