Any biomass can be used as feedstocks for AD. However, biomass wastes, espe­cially those with a relatively high water content (>50%), are the most common feedstocks suitable for AD. In fact, methane biogas has been produced from mil­lions of tons of biomass wastes arising from municipal, industrial and agricultural sources [91]. The characteristics of biomass wastes vary widely. The common feed­stocks suitable for AD have been discussed with respect to features pertinent to AD and biogas potentials by Yu et al. [91]. The AD of several types of feedstocks has also been reviewed recently (e. g., [15, 66, 85]). Anaerobic digesters can be cat­egorized in many different ways (see [80, 91] for an overview). No AD reactor is universally ideal or superior because each type of reactor has certain advantages and disadvantages that make it appropriate for particular type(s) of feedstocks. In this chapter, the features of individual feedstocks that have substantial methane biogas potentials and the AD technologies that are suitable for their AD will be discussed.