A better understanding of the pathophysiology of progressive renal scarring has emerged from the research undertaken over the last decade. It highlights the respective roles of glomerulosclerosis and tubulo-interstitial fibrosis in the progression of renal insufficiency and scarring. Similarities have been identified between the process of glomerulosclerosis and that of atherosclerosis. In both instances an important role has been attributed to growth promoting factors in particular PDGF and TGF-beta. Similarly, tubulo-interstitial scarring also involves interactions between tubular cells, inflammatory cells and fibroblasts/myofibroblasts mediated by growth factors. The understanding of the contribution of growth factors to experimental renal scarring has led to therapeutic interventions based on their manipulations. It remains to be determined whether such therapeutic approaches will prove beneficial to patients.