Abstract: The adsorption behavior of rice husk and its ash for cadmium ions from aqueous solutions has been investigated as a function of appropriate equilibrium time, amount of adsorbent, concentration of adsorbate, pH and particle size using a batch system. Studies showed that pH of aqueous solutions affected cadmium removal as a result of removal efficiency increased with increasing solution pH. The maximum adsorption was about 97.2 and 99.2% for rice husk and rice husk ash, respectively, at pH 6, contact time 180 min and initial concentration of 20 mg L -1. Desorption of cadmium was 9% at pH 6. The cadmium sorption obeyed both the Langmuir and Fraundlich isotherms. The studies showed rice husk ash was more favorable than rice husk in removing cadmium and thus was a better adsorbent.