Folliculogenesis and steroid production are the bases of fertility in the female mammal. Follicle stimulating hormones (FSH) plays an essential role in this process. It is clear that a variety of ovarian autocrine and paracrine factors can regulate this FSH receptor signal. In the past decade, it is established that growth factors, particularly insulin like growth factor and insulin like growth factor binding protein can modulate FSH receptor signal directly or indirectly. In addition to the folliculogenesis, it is possible that growth factors play a key role in follicle selection and atresia. With increased understanding of the intraovarian regulators in folliculogenesis, it becomes clear that several other autocrine paracrine factors may exist in intraovarian regulation of folliculogenesis, including steroid hormones, cytokines, inhibin, activin.