Despite considerable progress in medical research, cancer is still one of the high-ranking causes of death in the world. It is the second most common cause of death due to disease after heart disease, and according to World Health Organization it will be the cause of death for more than 10 million people in 2020; therefore, one of the main research goals for researchers investigating new anticancer agents. But the major complication for the cancer cure without surgeries is side effects. Especially, cytotoxic anticancer chemotherapeutic agents generally produce severe side effects, while reducing host resistance to cancer and infections. Therefore, it is important to find new, powerful anticancer agents that are highly effective, biodegradable, and biocompatible. Chitin and chitosan are biopolymers which have unique structural possibilities for chemical and mechanical modifications to generate novel properties, functions. These biopolymers are biocompatible, biodegradable, and nontoxic, and their chemical properties allow them to be easily processed into gels, sponges, membranes, beads, and scaffolds forms also. Due to their unique properties, they are excellent candidates for cancer cure or cancer diagnosis.