Some features of the nephrotic syndrome (NS) were studied in 38 patients with mesangial proliferative glomerylonephritis (MSPGN). Clinicomorphological correlations were deduced, 10-year survival rates were determined. NS in MSPGN can be observed both in diffuse and focal variants, results in clinicomorphological remissions and is not attended by renal functional disorders in most of the patients. The best therapeutic results were achieved with glucocorticosteroids. The 10-year survival rate was 88%. It is assumed that NS main morphological substrate in MSPGN is, first of all, podocytic small outgrowths destruction.