Quality control of dialysis treatment has received wide attention since inadequate dialysis dose was an independent risk factor of morbidity and mortality in hemodialysis patients. Each 0.1 decrease in Kt/V less than 1.2 is estimated to increase the relative risk of death by 5–7%. A higher Kt/V can be achieved by increasing treatment time, using a larger dialyzer or increasing blood or dialysate flow rates. The aim of this cross-sectional study was to know, using online conductivity monitor (OCM) routinely, whether a certain subgroup of patients is being treated inadequately. 24 anuric patients were included in a cross-sectional study: 20.8% were diabetics, mean age 64.7 ± 18.2 years; 16% females. Access blood were AVFI and the effective dialyzed blood flow was set at 350 mL/min, with recirculation <5%. BMI was 25.4 ± 3.8 kg/m2 and body weight was 69.7 ± 12 kg. All patients were dialyzed thrice weekly (245 ± 21 min) with dialysis machine 4008H (Fresenius Medical Care) equipped with OCM monitor and the hollow fiber high-flux polysulfone membrane (HF-80 1.8 m2) and helixone (Fx-60, 1.6 m2). Dialysate flow was maintained at 500 mL/min, with standard dialysate liquid. Drug therapy was not varied. OCM was validated for our population and reported in other abstracts (r2 = 0.96, p < 0.001). Inadequate dialysis dose was considered at OCM Kt/V less than 1.2. Data were processed and statistically analyzed with SPSS 11.0 software package. Watson volume (Wv) to other baseline characteristics was assessed by using contingency tables, t-tests, analysis of variance, and linear regression, as appropriate. All the tests were performed for a 0.05 significance level. The OCM Kt/V weekly was inversely related to Wv (r = −0.833, p < 0.001). 20.8% of our patients are at risk of inadequate dialysis dose, and it reflects our current practice of dialysis prescription. All of them are anuric young men with a Wv > 40 L. Specific efforts are required to deliver an adequate dialysis dose in this kind of patients. This can be achieved by altering dialysis frequency, increasing membrane surface, and/or increasing dialysis flow. OCM Kt/V device permits a daily dialysis dose delivery and, consequently, an individualized prescription. Prospective studies are required to establish whether adequate dialysis dose in patients with Wv > 40 L may further improve their survival.