Most ovarian follicles that begin to grow and develop fail to reach ovulatory status but instead degenerated by apoptosis (programmed cell death) of follicular cells. Ovarian follicle atresia is a common phenomenon in vertebrate ovaries and this process is characterized by follicular wall degeneration .The molecular mechanism underlying follicle atresia is apoptotic granulosa cell death Apoptosis is a genetically determined and active event, i.e., dependent on the balance of pro-and anti-apoptotic genes and requires energy. Apoptosis is mediated by active intrinsic mechanisms and extrinsic factors, this process is conserved in terms of evolution, by which cells inactivate, disassemble and degrade their own structural and functional components systematically for completion of their own death. Ability of cells to enter in apoptosis in response to a specific death signal depends on both their proliferative status and position in cell cycle, and on controlled expression of genes that promote, inhibit or affect cell death program. Thus, a better understanding of the mechanisms involved in atresia is necessary to avoid the great follicular loss that occurs in vivo and to maximize female reproductive potential.