The paper deals with a study into the state of renal-pressor humoral factors and morphological changes in the kidneys at early stages of inception and formation of hypertensive disease. By applying the radioimmunological method of determining renin in patients with the IIA and IIB stages of the disease--two groups among them, with normal or an elevated renin activity and with its low level were recognized. In analyzing morphological features of renal tissue obtained through biopsy it was found that in 2/3 of patients with the IB and IIA stages of hypertensive disease no changes in the kidneys were demonstrable. In 1/3 of the patients there were in evidence organic alterations in the form of arteriolohyalinosis, proliferation and fibrosis of the intima, myoelastosis, myoelastofibrosis involving the media of intrarenal arteries of diverse calibre, dystrophic changes in the tubular system, partial glomerular hyalinosis, hypertrophy and hyperplasia of the juxtaglomerular apparatus.