Abstract: To investigate the regulation of Ghrelin on the hypothalamus and pituitary of rat. The localization of Ghrelin and its mRNA in hypothalamus and pituitary tissues were detected by immunohistochemical PV-9000 2-step and in situ hybridization, respectively. Results showed that Ghrelin and its mRNA was mainly distributed in the arcuate nuclei, ventromedial nucleus, median eminence, periventricular nucleus of hypothalamus and anterior pituitary, the colour of cells in nuclei were different. A large number of positive cells were found in anterior pituitary, no positive cells were distributed in neurohypophysis. Ghrelin and its mRNA were both presented in the hypothalamus and pituitary tissues of rat, which suggested that the Ghrelin may play a role in the secretion of gonadotropin-releasing hormone and gonadotropin.