Adsorption of uranium (VI) from aqueous solution onto Yukitsubaki carbon (YKC) modified with nitric acid (10% and 30%) has been investigated in a batch system. Adsorption parameters such as contact time, carbon dosage, pH of solution and temperature onto the modified carbon have been determined with ICP-MS in order to obtain the optimum conditions for the U(VI) adsorption process. Adsorption isotherms of U(VI) onto the modified and pristine carbon were measured at varying initial concentrations under optimized condition. The surface properties of the modified carbon as well as the pristine carbon were characterized using N-2-BET, SEM and FT-IR. The results show that the U(VI) adsorption capacity of YKC is increased after the modification with nitric acid, and that the Langmuir isotherm model fits the experimental data better than the Freundlich isotherm.