To investigate the expression of osteopontin (OPN) and its receptor integrin alphanubeta3 in the placental tissue from pregnant women complicated with preeclampsia, the expression of OPN and alphanubeta3 in the placenta of the pregnant women with preeclampsia and healthy pregnant women was detected by immunohistochemistry, Western blotting and RT-PCR. Our results showed that OPN and alphanubeta3 protein were expressed in the placenta from normal pregnant woman and those with preeclampsia. OPN was located in the placental syncytiotrophoblasts and the cytoplasm of capillary endothelial cells and integrin alphanubeta3 was mainly expressed on the surface of trophoblast cells. Expression of OPN and integrin alphanubeta3 in the placental tissue from preeclampsia subjects was significantly lower than that from the control group (P<0.05). Compared with the control group, expression of OPN in the placental tissue from preeclampsia group was significantly lower (P<0.05) but there was no significant difference in the expression of alphanu and beta3 between the preeclampsia group and the controls. It is concluded that OPN and its receptor integrin alphanubeta3 may be involved in the pathogenesis of preeclampsia.