The success of lignocellulosic biofuels and biochemical industries depends on an economic and reliable supply of high-quality biomass. Many research and development efforts, however, have been historically focused on the utilization of agriculturally derived cellulosic feedstocks, without considerations of their low energy density, high variations in compositions and potential supply risks in terms of availability and affordability. This book chapter demonstrated a strategy of feedstock blending and densification to address the supply chain challenges. Blending takes advantage of low cost feedstock to avoid the prohibitive costs incurred through reliance on a single feedstock resource while densification produces feedstocks with increased bulk density and desirable feed handling properties as well as reduced transportation cost. We also review recent research on the blending and densification dealing with various types of feedstocks with a focus on the impacts of these preprocessing steps on biochemical conversion, i.e., various thermochemical pretreatment chemistries and enzymatic hydrolysis, into fermentable sugars for biofuel production.