Introduction. The rates of morbidity and mortality in patients receiving routine hemodialysis have been demonstrated to be significantly affected by the dose of HD. As the national and international standards for determination of dialysis adequacy vary among countries, it is necessary to investigate the optimum criteria for HD adequacy. In this study, we aimed at comparing HD adequacy, through two methods of OCM with electrical conductance, and blood-driven Kt/V of urea, in the largest hemodialysis center in Iran. Methods. The value of UC, as an indicator of HD adequacy, was measured 301 times in 120 HD patients via two methods of OCM and blood-driven clearance of urea. For urea-driven Kt/V, two blood samples, each 2 milliliters, were taken from the patient, one before and one after a HD session. For OCM, Fresenius 4008 dialysis machine was set online once the patient was receiving HD. The results of these two methods were analyzed regarding the correlation with patients’,demographics, BMI, required weekly HD sessions, type of HD access, type of dialyzers, hematocrit, UDV, ultrafiltration, and blood flow rate. Results. The mean values of UC obtained from blood samples and OCM were almost similar and not significantly different (1. 20 vs. 1. 11, P =. 50). UC values, measured by laboratory assessments were significantly associated with gender, BMI and UDV, while UC values from OCM were significantly associated with gender, BMI, dialyzer type, UDV and ultrafiltration. Conclusions. We conclude that OCM can be used as an effective substitute for laboratory assessment in HD centers to assess HD adequacy.