Because there have only been a few reports evaluating the absolute value of circulating blood volume (CBV) in hemodialysis (HD) patients, we measured CBV in 15 HD patients using pulse dye-densitometry (PDD) in this study. We evaluated the correlation between CBV by PDD (CBV-PDD) and the calculated CBV using three prediction formulas (CBV1 : body weight×0.077, CBV2 : body surface area : 2.68, CBV3 : ogawa & fujita method), respectively. Furthermore, we also evaluated differences in calculating the plasma refilling rate (PRR) and mean plasma refilling coefficient (mean Kr) by CBV-PDD or CBV1. First, there was a significant and positive linear correlation between CBV-PDD and CBV1, CBV2 and CBV3 before HD (CBV-PDD vs. CBV1 ; r=0.56, vs. CBV2 ; r=0.60, vs. CBV3 ; r=0.58, p<0.05, respectively) and there was no difference on analysis by Bland-Altman plots. Second, there was no difference between PRR by CBV-PDD and by CBV1 (CBV-PDD ; 86.9±1.8, CBV1 ; 87.9±1.7%), and mean Kr calculated by CBV-PDD and CBV1 (CBV-PDD ; 2.5±0.4, CBV1 ; 2.6±0.4 mL/min/mmHg). Therefore, we concluded that the evaluation of CBV and vascular permeability in HD patients showed almost the same values measured by PDD and calculated by prediction formulas. Therefore, the evaluation of body fluid using either prediction formulas or PDD is clinically useful.