Objective: To study the relation of plasma Se to oxidative stress in the patients with primary glomerular diseases (PGS) and its clinical significance. Methods: Plasma Se concentration ,GSH-Px and SOD activities and contents of MDA in 45 patients with PGS and 20 normal control (NC)were measured by catalytic polarography and colorimetric assay. Serum creatinine, urea nitrogen and uric acid concentrations in these patients were determined simultaneously. Results: 1. Plasma Se contents of both PGS patients of normal(groupⅠ) and impaired renal function (groupⅡ) were significantly lower than those in NC;2. PGS patients of groupⅠandⅡhad significantly lower plasma GSH-Px and SOD activities than NC and their MDA contents were siginificantly higher. 3. Plasma GSH-Px and SOD activities and MDA contents between groupⅠand Ⅱ were not different; 4. Multiple logistic regression analysis showed that plasma Se content in patients with PGS was positively related to plasma GSH-Px , SOD activities and negatively correlated with MDA. Serum creatinine concentrations were negatively correlated significantly with plasma Se, GSH-Px, SOD and positively related to MDA. Conclusion: Plasma Se deficiency may be an important non-immune factor resulting in or worsening PGS through weakening body抯 antioxidative defence. It is suggested that sufficient Se supplementation in practice may be obviously beneficial to oxidative stress in the patients with PGS.