The hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, the Met protein tyrosine kinase, form a classic ligand-receptor system for epithelial-mesenchymal communications in the normal and cancerous prostate. This review illustrates the expression and activities of HGF/SF and Met during prostate development, homeostasis, and carcinogenesis. The participation of HGF/SF in the morphogenetic program of rodent prostate development, the role of Met in normal human prostate epithelium, and underlying mechanisms of deregulated Met expression in localized and metastatic prostate cancer are discussed. On the basis of the commonly observed overexpression of Met in metastatic prostate cancer, HGF/SF-Met-targeted imaging and therapeutic agents can now be applied toward diagnosis and treatment.