The poor degradability, decommissioning of landfilling sites and the inflating water, wastewater, solid wastes and land pollution concerns and pollution episodes have unanimously urged the global scientific and engineering community to ponder deeper on plastics. The prolific use of plastics in the last three decades has placed much burden on the actual capacities available for plastic waste disposal. This has soon led to the need for biodegradable plastics. Heightened awareness of the polymeric waste problem, and the several environmental impacts, has fostered renewed interest in the area of biodegradable polymers synthesis, characterization, applications and biodegradability. This chapter will approach the biodegradation of biodegradable polymers through discussions on the general mechanisms of polymer biodegradation, the essential dynamics of the composting process and the progress achieved in research on the degradation of polyhydroxyalkanoates (PHAs), poly(lactic acid)â based polymers (PLAs), polyethylenes and polyâ εâ caprolactones (PCL) in the composting environment.