Lignocellulose biomass is a complex that mainly consists of cellulose, hemicellulose, and lignin [1]. The composition of these compounds directly depends on their source, whether hardwood, softwood, or grass. Cellulose with a particular crystalline structure that is insoluble in water is resistant to depolymerization. Hemicellulose, which provides structural backbone to plant cell wall, is a branched polymer of glucose or xylose. According to literature [2], cellulose and hemicellulose are probable sources of fermentable sugars. These sugars are first produced after a pretreatment process of cellulose polymer, followed by enzymatic hydrolysis. Lignin provides further strength to plant cell walls, but hinders the enzymatic hydrolysis of carbohydrates. Several chemical pretreatment approaches have been developed to remove hemicellulose and lignin and decrease the crystallinity of cellulose to enhance the biodegradability of cellulose and sugar yield in enzymatic hydrolysis to maximize the volumetric productivity of the cellulosic feedstock. Highly digestible solids that enhance sugar yields while avoiding the degradation of sugars and minimizing the formation of inhibitors for the subsequent fermentation steps are produced during the treatment process. These technologies are cost effective, with minimum heat and power requirements; they are also environment friendly [3]. This study aims to review promising chemical pretreatment methods with emphasis on suitable feedstock these methods are used for and the merits and disadvantages of each method. This paper shows the importance of the pretreatment process for the subsequent enzymatic hydrolysis and conversion of cellulosic feedstock to valuable products in fermentation. Fig. 1 represents the pretreatment steps that finally lead to the generation of sugars as substrates for biofuel production.