BACKGROUND The aim of this study was to observe the concentration of serum anti-PLA2R antibody in idiopathic membranous nephropathy (IMN) patients and analyze its relationship with clinical and laboratory parameters. MATERIAL AND METHODS We treated 72 patients with idiopathic membranous nephropathy diagnosed by renal biopsy; all these patients who presented nephrotic syndrome were enrolled for investigation, and then underwent combination therapy with prednisone and cyclosporine A for 6 months. We collected data on 24-h total proteinuria (TUpro), creatinine clearance rate (Ccr), and serum albumin (Alb) levels before and after immunosuppressive treatment. Serum anti-PLA2R antibody was measured by enzyme-linked immunosorbent assay (ELISA). RESULTS Fifty-six out of 72 IMN patients presented positive serum anti-PLA2R antibody. The titer of anti-PLA2R antibody was significantly correlated with both TUpro and serum Alb levels of pre- and post-therapeutic values in IMN (P<0.05), but did not have a relationship with Ccr (P>0.05). In comparison with the anti-PLA2R antibody-negative group, there were significantly higher TUpro and lower Alb levels in the anti-PLA2R antibody-positive group (P<0.05). However, Ccr was comparatively lower in the anti-PLA2R antibody-positive group, but the difference was not statistically significant (P>0.05). There were 24 patients with negative anti-PLA2R antibody and 14 patients had complete remission in the positive anti-PLA2R antibody group, while anti-PLA2R antibody of all 14 patients became negative. Eight out of 16 patients without anti-PLA2R antibody went into complete remission. CONCLUSIONS Serum anti-PLA2R antibody, as determined by non-invasive technique, is a specific biomarker for diagnosis of IMN. Our results suggest that serum anti-PLA2R antibody has great potential to guide clinical diagnosis and treatment, as well as prognosis determination, in IMN patients.