Objective To investigate the association between E/T (extracellular water to total body water ratio) and pulse wave velocity (PWV) in patients on continuous ambulatory peritoneal dialysis(CAPD). Methods Clinical stable CAPD patients (n=56,26M/30F) in one single center were included. Carotid-femoral PWV was measured with a validated automatic device and was used as an index of large arterial stiffness. Multiple-frequency bioelectrical impedance analysis was used to record the values for ECW, intracellular water (ICW), and total body water. Based on these data, E/T was also calculated. In addition, some biochemical indices, such as serum albumin, blood urea nitrogen, serum creatinine, serum triglycerides, total cholesterol lipoprotein, low-density lipoprotein, high-density lipoprotein, alanine and aspartate transaminase， etc were determined with standard methods. Pearson’s correlation and multiple regression analysis were performed to identify the relationship between E/T and PWV. Results PWV was strongly associated with E/T (r = 0.454, P = 0.001), E/I(r = 0.456, P = 0.001), pulse pressure(PP)（r =0.649， P < 0.01）,age（r = 0.404, P = 0.002）, serum albumin（r= -0.346, P = 0.01）and CRP（r =0.327, P = 0.025）, respectively. Multiple regression analysis showed that PWV was independently determined by E/T（β＝ 0.472, P = 0.001）, PP(β= 0.442, P = 0.001) and CRP(β= 0.246,P = 0.05). They accounted for 58.1% of the total variance and E/T alone represented 37.8% of the explained variance. Conclusions E/T is closely associated with PWV in CAPD patients. E/T, in addition to PP and CRP, is an independent risk factor for elevating PWV in CAPD patients, suggesting that the increase of arterial stiffness may be the link between fluid overload and cardiovascular events and mortality in CAPD patients.