Chitin, isolated from shrimp shell, was subjected t o acid and alkali treatment. The effect of alkali a nd acid pretreatment of chitin on phosphorylation of chitin was investigated. Also the effect of alkali and a cid pretreatment of chitin on the extent of phosphorylation in prese nce of cross-linker was illustrated. Acid pretreatm ent was found to be more efficient in increasing the reactivity of c hitin toward phosphorylation than alkali pretreatme nt. The prepared chitin derivatives were investigated for h eavy metal ions removal (Ni, Mg, Zn and Pb). Phosph orylated and also carboxylation of chitin (in presence of cr osslinker) have increased capability toward heavy m etal ions removal more than chitin. Also, phosphorylated cros s-linked chitin treated with acid showed the highes t heavy metal ion removal capability. Infrared spectroscopy (FTIR ) was used to follow the molecular structure of chi tin and its derivatives.