Morphogenesis of dystrophy of nephrocytes was studied by analysis of 106 biopsies of kidneys from patients with glomerulonephritis using light (semi-thin sections) and electron microscopy. The development of one or another kind of nephrocyte dystrophy was shown to be due to the deficiency of certain mechanisms of renal reabsorption and secretion associated with the corresponding membrane-enzyme systems of the cell. Therefore there is no ground to believe in transition of one kind of nephrocyte dystrophy into another as has been assumed until recently. The point is in the combination of various types of dystrophy (hyalino-drop, hydropic, fatty) within the object under study (biopsy), tubule, or even one nephrocyte. The analysis of the data obtained permits some general conclusions to be made with regard to the morphogenesis and the essence of dystrophy.