【Abstract】Objective To assess the value of plasma brain natriuretic peptide (BNP) for the prediction of fluid overload after the measurements of volume load status by bioimpedance analysis (BIA) and plasma brain natriuretic peptide (BNP) level in maintenance hemodialysis (MHD) patients. Methods We enrolled 74 MHD patients treated in the Blood Purification Center of Peking University International Hospital in this study. Overhydration before hemodialysis in the day of plasma BNP assay (OHbnp) was evaluated by BIA.Echocardiography was performed within two weeks after BIA. The patients were then divided into two groups, the normal fluid load group (OHbnp ≤2.5L) and the fluid overload group (OHbnp＞2.5L). Plasma BNP level and other parameters were compared between the two groups. Multivariate linear regression was used to assess the variables related to BNP. Receiver operating characteristic (ROC) curve was used to investigate the BNP level for the diagnosis of fluid overload in MHD patients. Results BNP was significantly higher in the fluid overload group than in the normal fluid load group [209 (116,395) pg/ml vs. 339 (172, 843) pg/ml,t=-2.197, P=0.028]. Multivariate linear regression revealed that plasma BNP was closely related to the levels of OHbnp (β =0.107 ± 0.037, P=0.005), hemoglobin (β =-0.012±0.004, P=0.005) and lean tissue index(β=-0.046±0.019, P=0.016). ROC curve revealed that the sensitivity and specificity for the diagnosis of fluid overload were 0.548 and 0.698 respectively, when the cut-off value of BNP was set at 309 pg/ml. Conclusion Plasma BNP level was affected by the levels of fluid load, hemoglobin and lean tissue index. Plasma BNP >309 pg/ml suggests the presence of fluid overload.