Cancer is the leading cause of death all over the world and chemotherapy is an important approach to fight cancer, however, there are many obstacles against successful cancer chemotherapy such as development of multidrug resistance, poor solubility of chemotherapeutic agents and adverse side effects to healthy tissues. An important strategy to overcome these obstacles, is the use of nanotechnology. In recent years, natural polymers such as cellulose and its nanoform structure, nanocrystalline cellulose (NCC), have attracted the interest of researchers in the field of nanotechnology and specially drug delivery systems, due to biocompatibility and biodegradability of NCC. Cellulose is the most abundant natural biopolymer and changes to NCC by several chemical and mechanical methods. In this review, we mainly focus on the methods for production of NCC, physicochemical properties and medical applications of NCC (e.g. regenerative medicine, replacement of vascular grafts, tissue engineering, anti-bacterial/anti-viral applications, diagnosis and biosensing) with a special emphasize on drug delivery systems.