Armenian birch mouse is one of the least known species of mammals of Eurasia. It was described as a separate species based on three specimen trapped in 1986. From that time no other Sicista was found in Armenia. In 2015 we surveyed Central and Northern Armenia and established that probably population from the type locality is lost. But we found another population on Sevan Pass. Due to our observations the species meets Critically Endangered B2a+bIV category of the IUCN Red List.