The extraction behavior of uranium in a multicomponent system simulated on the basis of high-level liquid waste was examined in order to find effective conditions for the removal of residual uranium in a simulated radwaste solution by the TBP solvent extraction method. While the conventional semiempirical equation for the distribution coefficient of uranium could be used in a system composed of only uranium and nitric acid, it was found to be unsuitable for a multicomponent system where the concentration of uranium is not dominant. Uranium extractability by TBP was found to be limited in multicomponents systems regardless of high TBP concentration, phase ratio, and extraction times because of the presence of neodymium and iron together with uranium in the systems.