A method based on adsorption phenomena has been established for the removal of cadmium from aqueous solution by activated charcoal. Experimental conditions were optimized for the maximum uptake of cadmium by charcoal in terms of shaking time, pH, amount of charcoal, cadmium ion concentration, and temperature. Maximum adsorption was observed at 4.0 pH within 20 min equilibrium time. Various adsorption isotherms, i.e., the Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) have been applied to the adsorption data. The sorption mean free energy from the D-R isotherm was 3.07 +/- 0.05 kJ mol(-1) indicating physical nature of adsorption. The adsorption of cadmium increased with the increase in temperature. Thermodynamic quantities Delta H, Delta S, and Delta G were calculated for the adsorption process. The method was tested by removing the cadmium from cadmium-spiked tap water using activated charcoal. It was observed that about 70-75% cadmium could be removed by activated charcoal in a single step.