We can quantify the adequacy of hemodialysis (HD) as the dialysis dose using urea kinetic modeling (UKM). Though the one-compartment model (1CM) has frequently been applied, there are some studies which have successfully applied the two-compartment model (2CM) including urea rebound. To clarify whether 1CM or 2CM is more acceptable, we analyzed 100 patients using UKM, applying each model. The dialysis dose was defined as the logarithm of pre-/post-HD urea volume in the body. In about half the patients analyzed, 1CM estimation of the dialysis dose exceeded 2CM estimation by more than 10%, and the 1CM was not considered to be acceptable.