A single screw extrusion process in which CO2 is injected into the polymer melt has been utilized to produce low density biodegradable poly(DL-lactic acid) (PDLLA) foams. High pressure differential scanning calorimetry (DSC) and rheology are used to observe the melting point and viscosity depression of PDLLA 3051D in the presence of CO2. Foams of PDLLA 3051D are produced in a static environment under a range of conditions, and these data are utilized to extrude PDLLA 3051D into foamed sheets for packaging applications. The density, crystallinity, mechanical properties and microstructure of these foams are evaluated.