In recent years there have been tremendous advances in the fields of chemistry, physics and biology which have a direct impact on advances in biomaterials science. These advances have contributed significantly to the improvement of modern health care and continue to influence the practice of medicine. A biomaterial is any material, natural or man-made, that comprises whole or part of a living structure or biomedical device which performs, augments, or replaces a natural function. Among the biomaterials, chitin and chitosan have received much attention due to their non-toxicity, biodegradability, biocompatibility and multifunctional properties with applications in biomedical and pharmaceutical sciences. The main driving force behind the development of new applications for chitin and its derivative chitosan lies with the fact that these polysaccharides represent a renewable source of natural biodegradable polymers. Since chitin is the second most abundant natural polymer, academic as well as industrial scientists are faced with a great challenge to find new and practical applications for this material. This book provides an examination of the state of the art, and discusses current research as well as new biomedical applications of chitin and chitosan. Applications of chitin and chitosan will be of interest to industrial personnel involved in bioprocessing as well as bioengineering students, specialists in the biomedical and biopharmaceutical industry, biochemists, food engineers, environmentalists, and microbiologists and biologists who specialize in chitosan technology. The subject matter of the book is divided into nine chapters. Chapter 1 deals with the preparation and physico-chemical properties of amphiphilic derivatives of chitin and chitosan. The potential applications of these derivatives in the fields of controlled drug and gene delivery are discussed in details. Chapter 2 deals with the inhibitory activity of chitosan against bacteria and fungi potentially encountered in foodstuffs and the modes of action as suggested in the literature. Recent approaches, such as enzymatic depolymerization and chemical modifications, developed to improve the bioactivity of chitosan are reported. In addition, the applications of chitosan based products as biopackaging materials in food preservation are explored. In chapter 3, the recent developments and applications of stimuli-responsive materials based on chitosan are discussed. Moreover, different approaches used to prepare chitosan interpenetrating networks are analyzed and the potential of the resultant system for biomedical applications are critically reviewed. Different methods of chitosan deposition onto substrates for tissue engineering, wound dressing, separation membranes, biocompatible and antibacterial coatings, stent coatings, and sensors applications are reported in chapter 4. Chapter 5 of this book deals with the mechanisms involved in the in vitro calcification of chitosan while chapter 6 discusses the role of chitosan and its derivatives as potent adjuvant/delivery systems for mucosal immunization both in human and veterinary medicine. The current research and developments on chitin and chitosan nanoscaffolds for tissue engineering applications and future demands on bio-products are discussed in chapter 7. Chapter 8 reviews the different techniques of chitosan microsphere preparation for the drug delivery applications. In addition, the advantages of using chitosan microsphere as drug carrier are also explored. Recently, considerable works have been directed to develop an ideal scaffold based on polymer/ceramic composite materials. In this context, chitosan/calcium phosphate composite materials would have an importance in bone tissue engineering. The preparation methods, properties and applications of composite scaffolds and cements based on calcium phosphate and chitosan are reported in chapter 9. We hope this book can serve as a comprehensive introduction to researchers in biomaterials science and engineering in general, and can also be used as a graduate level text in related areas. We thank the authors for their excellent contributions to this book and our publishers for their encouragement which motivated us to produce this book. We believe this will make a lasting contribution to the field of biomaterials science.