Assessment of dry weight in hemodialysis patients is essential. Intravascular hypervolemia increases the levels of digitalis-like immunoreactive substance (DLIS), atrial natriuretic peptide (ANP) and it alters echocardiographic parameters. The basal levels of DLIS in forty-two hemodialysis patients were significantly higher when compared with control (n:20) (p< 0.05). Since endogenous DLIS gives cross-reaction to anti-digoxin antibodies, the levels of DLIS were determined by two seperate techniques, FPIA (fluorescence polarization enzyme immunoassay) and MEIA (microparticle enzyme immunoassay). The strong positive correlation between DLIS-FPIA and DLIS-MEIA (r:0.894, p<0.001) made us think that these two markers could be used interchangeably. Compared to the corresponding parameters of forty-two hemodialysis patients, DLIS and ANP levels and diameters of right and left atria of eleven patients, selected as hypervolemic by conventional criteriae, were higher. After three months of ultrafiltration treatment, we determined that the levels of DLIS, ANP and diameters of both atria decreased significantly approaching control levels. We concluded that the tests of DLIS and ANP combined with atrial echocardiographic parameters were useful to determine the intravascular volume response to ultrafiltration treatment.