A descriptive survey of renal hemodynamics in the major experimental models of progressive renal disorders (primary loss of renal tissue, primary glomerular injury and primary hypertension) is given. Although the pathogenesis in the different models differs in several respects, increases in glomerular capillary pressure and renal growth factors are important for the development of progressive renal disorders. In primary glomerular disorders, interstitial immune reactions seem to be critical. In glomerular nephritis with increased capillary wall thickness, the increase in glomerular capillary pressure may be of less importance than in other models. A third important factor for progression of renal disorders is a gradual breakdown of autoregulation of renal blood flow and glomerular filtration rate exposing the glomerulus to the variations in systemic blood pressure.