Abstract: An extension of the Aksu Jabagly nature reserve is suggested in order to improve effectiveness of rare and endemic species conservation in the West Tien Shan. The existing area of the nature reserve is large enough for conservation and reproduction of most of the large mammal species such as ibex, bear, wild boar, snow leopard; the area is however insufficient for species such as Tien Shan argali, roe-deer, whose seasonal migrations extend beyond the area of the nature reserve, as well as Menzbier's marmot a rare endemic to the West Tien Shan, whose habitat is situated 10 15 km from the nature reserve.