Progression to end-stage renal failure is the final common pathway of many forms of glomerular diseases, independent of the type of initial insult. Tubulointerstitial fibrosis is tis near invariable finding and significant prognostic feature. We have reviewed immunological (cytokines, inflammatory cells) and nonimmunological factors (extracellular matrix proteins and proteolytic enzymes), being involved in mechanisms leading from glomerular disease to tubulointerstitial scarring, from the point of view of potential clinical usefulness of measuring its urine activities and levels to noninvasive diagnostic of kidney diseases.