This study was designed to detect the effects of fibronectin (FN) and leukaemia inhibitory factor (LIF) on matrix metallopoteinases (MMPs) of mouse blastocysts. The experiments comprised four groups: first, blastocysts grew on the dishes with FN-coated; the second, without FN-coated; the third group, without FN coated, but with 20 ng/μL LIF added to culture medium; and the fourth group, with both FN-coated and 20 ng/μL LIF added. Using MMP-2 and MMP-9 primers respectively, the expressions of MMP-2 and MMP-9 were detected by RT-PCR and cloning identification. The results showed that in the first group, MMP-2 and MMP-9 were produced after 12 and 24 h culturing; in the third group, there were both MMP-2 and MMP-9 bands when blastocysts were cultured for 24 h; and in the fourth group, MMP-2 and MMP-9 bands appeared when blastocysts were cultured for 6, 12 and 24 h. But in the second group no MMP-2 or MMP-9 band appeared. These results show that FN may initiate the transcription of MMP-2 and MMP-9 genes to This study was designed to detect the effects of fibronectin (FN) and leukaemia inhibitory factor (LIF) on matrix metallopoteinases (MMPs) of mouse blastocysts. The protocolslative four groups: first, blastocysts grew on the dishes with FN-coated; the second , without FN-coated; the third group, without FN coated, but with 20 ng / μL LIF added to culture medium; and the fourth group with both FN-coated and 20 ng / μL LIF added. MMPs were detected by RT-PCR and cloning identification. The results showed that in the first group, MMP-2 and MMP-9 were produced after 12 and 24 h culturing; in the third group, there were both MMP-2 and MMP-9 bands when blastocysts were cultured for 24 h; and in the fourth group, MMP-2 and MMP-9 bands were cultured for 6, 12 and 24 h . But in the second group no MMP-2 or MMP-9 band. These results show that FN may the transcription of MMP-2 and MMP-9 genes to