This present study first reported 8 cases of Thin membrane nephropathy (TMN) in China. Most patients had persistent microscopic hematuria, who could be accompanied with mild proteinuria or macroscopic hematuria. The contrast microscopy showed glomerular hematuria in the majority of the cases. Some patients (25%, 2 cases) had familial hematuric histories, suggesting this disease may be associated with heredity. All the patients had normal renal function at following-up period (average 2.9 years), this result showed this disease was benign glomerular disease. LM showed pathological change is mild, IF was negative, diffuse thin GBM was outstanding change by EM. The thickness of TMN was 265 +/- 39 nm, the thickness of IgA GN and normal control were separately 383 +/- 32 nm and 398 +/- 34 nm, the thickness of TMN was significantly thinner than IgA GN and normal control (P less than 0.01). This study showed ultrastructural observation of glomeruli by EM was necessary to diagnose this disease.