The important role of the tubulo-interstitial system for the progression of glomerulonephritis (GN), is the cause of a continuous search for the proper markers of kidney tubules damage, which can be applied in clinical diagnosis. In the present work the activity of N-acetyl-beta-D-glucosamidase (NAG), its isoenzyme NAG-B, alanylaminopeptidase (AAP), gamma-glutamyltransferase (GGT), concentration of beta2-microglobulin (beta2M) and daily protein excretion in the urine of 37 patients with morphologically different glomerulopathies were measured. The serum creatinine was also controlled. The obtained results suggest that activity of NAG in the patients with GN has an intermediate connection with proteinuria and could be a cause of the inflammatory process of the kidney, but the activity of AAP is directly dependent on urine protein concentration. Systemic analysis of both partial and multiple correlation coefficients of the examined indicators creates new, additional possibilities in the estimation of activity and progress of GN.