Morphological and clinical analysis of 1177 renal biopsies from nonselected patients with essential hypertension revealed compensated benign nephrosclerosis in 775 cases. Decompensated benign nephrosclerosis was found in 251 cases, and secondary malignant nephrosclerosis was found in 151 cases. This article describes the morphological and clinical features of decompensated benign nephrosclerosis, which has received little recognition until now. The morphological and clinical features of secondary malignant nephrosclerosis, which is induced by hypertension, are also considered. There is also a discussion of the differentiation of the latter from primary malignant nephrosclerosis, in which stenosis of the preglomerular vessels develops in the presence of normal blood pressure and leads secondarily to renal hypertension.