Expression of fibronectin and vitronectin receptors was studied in normal human kidney tissues and renal tissue biopsies from patients with several types of glomerulonephritis. Immunofluorescent staining of the normal kidneys showed that fibronectin receptor was present along the glomerular capillary walls, and that vitronectin receptor was present in the vessel walls, but was almost absent from the glomerulus. In kidney tissues biopsied from patients with various renal diseases, expression of fibronectin and vitronectin receptors was correlated with increase in the mesangial expansion. Expression of these receptors was decreased in the sclerosed area and hyalinized glomeruli compared with normal tissues. Fibronectin and vitronectin receptors were occasionally colocalized in the glomeruli with fibronectin and vitronectin, respectively. In situ hybridization showed that fibronectin receptor mRNA and vitronectin receptor mRNA were expressed in the diseased glomeruli. These findings indicate that expression of fibronectin and vitronectin receptors was altered in human glomerulonephritis, and that integrin expression may be important in cell-matrix interaction in the diseased glomeruli.