This study is conducted as a requirement for the degree of Doctor of Philosophy in Universiti Sains Malaysia. Chitosan and its derivatives were synthesized and used for the adsorption of copper(II) and lead(II) ions in aqueous solution. Different parameters affecting the adsorption process were studied and analysed using several isotherm and kinetic models. Several possible adsorption processes governing the adsorption of copper(II) and lead(II) ions were also proposed in this study. It is hoped that this book will be useful for those studying on adsorption and especially in the removal of heavy metal ions.