【Abstract】Objective To investigate the association between anti-glomerular basement membrane antibodies against different target antigens and the clinical phenotypes of patients with anti-GBM disease. Methods The target antigens of 97 sera from patients with anti-GBM disease diagnosed in our hospitals in the period from 1998 to 2008 were investigated by enzyme-linked immunosorbent assay (ELISA) using recombinant human1, 2, 3, 4 and 5 (IV) NC1 as the solid phase antigens. Sixty- nine sera were further examined by indirect immunofluorescence using normal human renal tissue as the substrates. Sections were pre-treated with 6M urea to unmask the cryptic epitopes, and untreated sections were used to detect natural exposed epitopes. Their associations with clinical and pathological data were analyzed. Results 3 (IV) NC1 could be recognized by sera from all patients, 1 (IV) NCI by 56.7% sera, 2(IV)NC1 by 43.3% sera, 4 (IV) NC1 by 53.6% sera, and 5(IV)NC1 by 85.6% sera. The level of anti-3(IV)NC1 antibodies was the independent risk factor to the level of serum creatinine at presentation (r=0.308, P =0.003) and to the percentage of crescents in glomeruli (r=0.492, P <0.001). Patients with anti-5(IV)NC1 antibodies had a higher recognizing rate to natural exposed epitopes (67.3% vs. 30.0%, P =0.026). The level of anti-5(IV) NC1 antibodies was positively correlated with the percentage of cellular crescents (P =0.013). Patients with positive antineutrophil cytoplasmic antibodies (ANCA) had a lower recognizing rate to 1(IV)NC1 (7.3% vs. 26.2%, P=0.011) and 4 (IV) NC1 (7.7% vs. 24.4%, P=0.023). Conclusion The major target antigen of anti-GBM antibodies is 3(IV)NC, and the level of these antibodies is the independent risk factor to renal damage. Anti-5(IV)NC1 antibodies may recognize natural exposed epitopes on GBM, and these antibodies may play important roles in the pathogenesis of the disease. Anti-GBM antibodies from patients with positive ANCA have a narrow spectrum of target antigens.