Investigation of composition of biomass is an important pre-requisite for determining its suitability for various downstream applications. In recent times, food waste has emerged as a valuable biomass feedstock which could be valorized for production of fuels, chemicals and materials. Prior to use as a feedstock, it is pertinent to perform a detailed composition analysis and gather critical information about nutrient content including carbon, nitrogen and lipid. Additionally, analysis of minor constituents in food waste is significant to understand the possibility of their toxic or inhibitory effects during biotechnological conversions. Another abundant biomass source is manure which primarily arises from animal feeding operations. The major application of manure is land-applied fertilizer besides the recent investigations for fuel and energy. These intended applications demand complete characterization of nutrient content and quality. Thus, this chapter is focused on characterization and analysis of food waste and manure. Methods for sampling, handling and pretreatment of food waste and manure are discussed. Furthermore, a detailed nutrient analysis and equipment used for analysis is described. We further discuss the application of food waste processing techniques which could facilitate the characterization, treatment and product recovery.