Celastrus orbiculatus has been widely used as a traditional medicine for the treatment of many diseases including rheumatoid arthritis and odontalgia. In the present study, anti-metastatic activity of a methanolic extract from C. orbiculatus (MCO) was studied. A gelatin zymographic assay revealed that MCO has potent inhibitory effects on MMP-2 and MMP-9 activities in B16F10 melanoma cells. Moreover, MCO attenuated MMP expression via down-regulation of NF-${kappa}$B translocation to the nucleus. Melanoma cell migration and invasion were also down-regulated by MCO. In addition, MCO significantly suppressed lung metastasis in an in vivo model. These results strongly suggest that MCO may possibly be used as a valuable anti-metastatic agent for cancer treatment.