Activities of main components of the kallikrein-kinin system: tissue (renal) and blood plasma kallikreins, kininases I and II, bradykinin-activating activity as well as free kinins, were estimated in urine of patients with latent and nephrotic forms of glomerulonephritis as compared with those parameters in urine of healthy persons. Content of tissue kallikrein was decreased in urine of patients with nephrotic form of glomerulonephritis as distinct from the disease latent form and healthy persons. At the same time, urine of these patients with nephrotic form contained elevated amount of blood plasma kallikrein and other proteinases of blood plasma origin. Bradykinin-inactivating activity as well as activities of kininase I and II were increased in urine of patients with the disease latent form 2-, 7- and 2.5-fold, respectively, and in urine of patients with nephrotic form--40-, 45- and 40-fold, respectively as compared with normal state. Daily excretion of free kinins with urine of healthy persons constituted 6.6 +/- 0.9 micrograms-eqv of bradykinin (BK), in patients with latent and nephrotic forms of glomerulonephritis--1.7 +/- 0.3 and 2.8 +/- microgram-eqv BK, respectively. Three kinins were found in all the examined persons when urine was collected in acid medium: BK, lysyl-BK and Met-Lys-BK; content of BK was minimal in urine of healthy persons and maximal--in urine of patients with nephrotic form of the disease. Clinical importance of the patterns studied and their role in correction of treatment course of patients with nephrotic form of glomerulonephritis are discussed.