Nanocrystalline cellulose is a renewable nanomaterial that has gained a lot of attention for its use as a biomedical material due to its exceptional physical and biological properties, such as surface chemistry, low toxicity, biodegradability, and biocompatibility. These nanocrystalline cellulose-based biomedical materials are widely utilized in medical implants, drug delivery systems, wound healing, tissue engineering, cardiovascular disease, and antibacterial/antimicrobial activities. This chapter gives a brief description of the extraction, modification, and characteristics of nanocrystalline cellulose. The study also discusses the various processing techniques of Nanocrystalline-based nanocomposites. Furthermore, it provides an overview of the most recent advancements in nanocrystalline cellulose and their nanocomposites in the biomedical field. © 2017 Elsevier Ltd. All rights reserved.