There are at least three distinct taxa of woolly lemurs (genus Avahi) in western Madagascar. The range of Avahi occidentalis extends north and east of the Betsiboka River to the Bay of Narinda. Avahi unicolor occurs well to the north, including the Ampasindava peninsula and the Manongarivo Special Reserve. Here we describe a third Avahi population in central western Madagascar, which was discovered in the Bemaraha Strict Nature Reserve in the Tsingy de Bemaraha region, north of the Manambolo River. The description is based on a released type individual from which we obtained hair samples, photographs, and tape and video recordings. Its entire range is believed to be less than 5,000 km2, and forest loss, along with an observed continuing decline in numbers, indicates that this species should be considered Endangered or even Critically Endangered, according to the Red List criteria of the World Conservation Union-IUCN. Am. J. Primatol. 67:371–376, 2005. © 2005 Wiley-Liss, Inc.