Waste egg shell is used as adsorbent to treat cadmium bearing wastewater. Characteristics of cadmium ion removal by egg shell in synthetic wastewater was investigated for various parameters. This study shows the effect of reaction time, the amount of egg shell, concentration of cadmium ion, the size of egg shell, temperature and solution pH on the extent of cadmium ion adsorption from solution. Adsorption increased with the increase in reaction time, the amount of egg shell, temperature and pH. But the amount of adsorption decreased according to the increase in the egg shell size. This study also examines the adsorption isotherm and reaction kinetics for cadmium ion. The adsorption process was found to have a tendency to be endothermic and the adsorption isotherms for cadmium ion could be fitted closely by the Freundlich model.