The epithelial-mesenchymal transition (EMT) is a cellular process though which an epithelial phenotypecan be converted into a phenotype of mesenchymal cells. Under physiological conditions EMT is important forembryogenesis, organ development, wound repair and tissue remodeling. However, EMT may also be activatedunder pathologic conditions, especially in carcinogenesis and metastatic progression. Major signaling pathwaysinvolved in EMT include transforming growth factor β(TGF-β), Wnt, Notch, Hedgehog and other signalingpathways. These pathways are related to several transcription factors, including Twist, Smads and zinc fingerproteins snail and slug. These interact with each other to provide crosstalk between the relevant signalingpathways. This review lays emphasis on studying the relationship between EMT and signaling pathways incarcinogenesis and metastatic progression.