This study which is on reproduction and breeding of Jebeer Gazzelle, one of the endangered species in Iran, was launched through live capturing of five heads (two males and three females) from the wildlife sanctuary in Naybandan, Tabas.The live-captured Jebeers were transferred to a thirty hectares fenced area in Shir — Ahmad, Sabzevar. The biological and behavioral indices of Jebeer species such as: feeding, mating, reproductivity, death rate, population growth, as well as their behavior at the sight of human beings are discussed in this paper. The study procedures which were completed within a period of five years have demonstrated that the sex distribution among the lambs born each year is not equal. Also, the birth rate and death rate and the population growth have been estimated for each year. Territorialism among the male ones in the mating season resulted in brutal fighting and subsequently the death of the young males. Females matured at the age of six months and the first delivery was observed at the age of eleven months. Generally speaking, the population growth of Jebeers in the fenced area was significant except for the first years, however, their high death rate inhibited the population growth during the first years of their transfer.