A neuroblastoma is an extracranial solid tumor diagnosed in childhood. Since tumor metastasis is the main cause of death for most neuroblastoma patients, an understanding of the mechanisms that modulate cancer cell invasion is a key to developing more effective chemotherapeutic agents. In the current study, we examined to determine whether mulberry leaf (ML) extract effectively inhibits the invasion potential of neuroblastoma cells in vitro. ML extract was found to suppress cell invasiveness as well as the activity and expression of matrix metalloproteinase-2 (MMP-2) under both normoxia and hypoxia in neuroblastoma. ML extract downregulated the expression of hypoxia-inducible factor-1α (HIF-1α), a well-known regulator of tumor metastasis, and its downstream targets, vascular endothelial growth factor (VEGF) and glucose transporter-1 (GLUT-1). Taken together, these results suggest that ML extract has chemotherapeutic effects on neuroblastoma cells by regulating invasion potential, thereby controlling the metastasis of neuroblastomas.