Chitin and chitinases (EC 3.2.1.14) have an immense potential. Chitinolytic enzymes have wide-ranging applications such as preparation of pharmaceutically important chitooligosacchandes and N-acetyl D-glucosamine, preparation of single-cell protein, isolation of protoplasts from fungi and yeast, control of pathogenic fungi, treatment of chitinous waste, and control of malaria transmission. In this review, we discuss the occurrence and structure of chitin, the types and sources of chitinases, their mode of action, chitinase production, as well as molecular cloning and protein engineering of chitinases and their biotechnological applications.