Cellulose is the most abundant biopolymer synthesized in Nature. It is the main constituent of plant cells and significantly less expensive than cereals. Cellulose is a water-insoluble long-chain polysaccharide consisting of several hundred to thousands of D-glucose molecules of formal composition (C6H10O5)n and can be hydrolyzed to soluble sugars by various methods. The traditional acidic and enzymatic methods have a number of limitations, although the sugars are obtained in high yields in some cases. Due to their environmentally friendly behavior, recently developed heterogeneous catalysts are significant candidates for the depolymerization of cellulose into sugars. The major advantages of the catalytic conversion of cellulose are high activity and selectivity and easy separation of products from the reaction mixture. The sugars formed from cellulose have a wide range of applications as fuels and chemicals in chemical industries.