Hepatocyte growth factor (HGF), also known as Scatter factor, is a paracrine cellular growth, motility and morphogenic factor. Hepatocyte Growth Factor/HGF is a member of the peptidase S1 family, and is derived from a single chain precursor of 728 amino acid residues containing 4 kringle domains, 1PAN domain and 1peptidase S1 domain. The synthesized single chain of HGF is further processed into a bioactive heterodimer composed of the 69 kDa α-subunit and the 34 kDa β-subunit by a serine protease. Hepatocyte Growth Factor/HGF has no detectable protease activity. Alternative splicing of its gene produces multiple transcript variants encoding different isoforms. It is secreted by mesenchymal cells and targets and acts primarily upon epithelial cells and endothelial cells, as well as haemopoietic progenitor cells. Hepatocyte Growth Factor/HGF regulates cell growth, cell motility, and morphogenesis by activating a tyrosine kinase signaling cascade after binding to the c-Met receptor. Hepatocyte Growth Factor/HGF may also play an important role as a paracrine or endocrine mediator through an epithelial-mesenchymal interaction in wound-healing, tissue or organ regeneration, morphogenesis and carcinogenesis.