Abstract: Kisspeptin (KP) is a prodct of prepro-kisspeptin. KP is a key regulator of GnRH and LH secretion in the ewe. In this study, Effect of different phases of estrous cycle on kisspeptin expression in the arcuate nucleus of the ewe examined. Because of no difference between phases of cycle, we suggested that perhaps KP neurons involved in mediating of both positive and negative feedback effects of steroids to GnRH neurons.