Biodegradable polymers present a very narrow processing window, with the suitable processing temperatures close to the degradation conditions. The aim of this work was to analyze the foamability of a biodegradable polymer, namely the poly(lactic acid), PLA. Foam injection molding was conducted by using a blowing agent under high pressure and temperature to produce parts having a cellular core and a compact solid skin (the so-called "structural foam"). The effect of a physical blowing agent (PBA) on density and morphology of foamed parts was characterized. A masterbatch of PLA and talc was prepared and adopted to obtain a compound containing 3% of talc. On adding this percentage of talc to PLA it was possible to obtain foamed parts with a much better morphology. © 2014 Elsevier B.V. All rights reserved.