Objective To investigate the roles of matrix metalloproteinase-9, -2 (MMP-9, 2), and tissue inhibitors of metalloproteinase-1,2 (TIMP-1, 2) in pathogenesis of the accretio placenta. Methods The women with the placenta accrete were recruited and the placenta (23) and deciduas tissues (9) after labor were obtained, and the placenta (28) and deciduas (11) from women without the placenta accreta were obtained as control to get, too. The expressions of MMP-9, -2, TIMP-1, 2 in the placental and decidual tissues were analyzed by real-time PCR. Results mRNA expression of MMP-9 in the placenta accreta was (3.21?0.76) copies/?g total RNA, significantly higher (P