Modern chemistry plays a strong economic role in industrial activities based on biomass, with an increasing trend of the importance of its application from the deployment of biorefineries and the principles of green chemistry, which make use of the potential of biomass with decreasing impact negative environmental. In this context, analytical chemistry can contribute significantly to the supply chains of biomass, be it plant or animal origin; however, with the first offering the greatest challenges and the greatest opportunity for technical and scientific advances, given its diversified chemical constitution. This chapter presents a general outlook about the application of analytical chemistry to understand the biomass composition and to promote its usages.