This paper reviews the expression and localization of proteins of the TGF-beta system in the kidney, i.e. TGF-beta isoforms, latent TGF-beta binding protein, and receptors. There is heterogeneity of TGF-beta isoforms, binding proteins and receptors. TGF-beta s are more evenly distributed among different segments of the nephron than TGF-beta receptors, and are expressed by almost all cell types in the kidney. The spatial distribution of TGF-beta and its signaling receptor may help to better understand the biologic function of TGF-beta in the kidney.