A single screw extrusion process in which CO2 is injected into the polymer melt has been utilised to produce low density biodegradable poly(DL‐lactic acid (PDLLA) foams. High pressure differential scanning calorimetry (DSC) is used to observe the melting point depression of crystalline PDLLA 3051D in the presence of CO2. In addition, the effect of temperature (110 to 140 °C) and CO2 pressure (50 to 120 bar) on the viscosity of PDLLA 3051D, in the amorphous and crystalline forms, are investigated through the use of a high pressure rheometer. Foams of PDLLA 3051D are produced in a static environment, under a range of conditions, and these data are utilised to extrude PDLLA 3051D into foamed sheets for packaging applications. The density, crystallinity, mechanical properties and microstructure of these foams are evaluated using DSC, tensile testing and scanning electron microscopy (SEM).