Notch signaling is one of the major pathways involved in development and tumorigenesis. Activated Notch is correlated with increased migration, invasion and epithelial-to-mesenchymal-transition (EMT) in breast cancer. However, mechanism of Notch-mediated cancer progression is poorly understood. CYR61 is a secreted protein and its upregulation is also related to increased breast tumorigenesis and EMT. Microarray analyses revealed that CYR61 was differentially expressed in response to Notch activation in breast epithelial cells. We hypothesized that CYR61 is a downstream mediator of Notch during EMT, migration and invasion. To test whether Notch requires CYR61 during EMT, migration and invasion, two complementary approaches were followed: (i) CYR61 expression was silenced by using shRNA in MCF10A epithelial breast cell line in the presence of Notch activation, (ii) CYR61 was over-expressed in MDA-MB-231 cancer breast cell line in the absence of Notch activity. Then, expression of EMT markers was analyzed in mRNA and protein levels via RT-qPCR and immuno-blotting, respectively. Migration and invasion ability of cells were investigated by wound healing assay and a lab-on-a-chip-system, respectively. Here, it was shown that CYR61 inhibition decreased Notch-induced EMT, migration and invasion of MCF10A and CYR61 overexpression in the absence of Notch activity partially rescued Notch-mediated invasion in MDA-MB-231 cell lines. Our findings suggest that CYR61 may act in downstream of Notch and is regulated by Notch. When we consider importance of CYR61 in Notch-induced EMT and cancer progression, targeting CYR61 may hold promise to develop novel strategies for treatment of breast cancer in early stages.