Poly(lactic acid) (PLA) is a remarkable biopolymer for packaging applications because it derives from renewable resources and it presents the great advantage to be biodegradable[1]. Nevertheless its high stiffness, low thermal stability and brittleness does not allow the use of PLA in a wide range of applications. Rub-ber toughening of PLA is a promising strategy to improve its mechanical charac-teristics [2]. In this work blends of PLA with poly(butylene-adipate-co-terephthalate) (PBAT) have been studied; PBAT is an oil-based material, but bio-compostable, capable to improve thermal and rheological properties of PLA [3]. Tensile tests, Impact tests and Fracture Characterization of PLA-PBAT blends (prepared by extrusion and injection molding with HAAKE MiniLab MiniExtruder and MiniJet) obtained as a function of composition in terms of PBAT weight percentages were carried out to evaluate blends fracture behavior. The results were discussed by using different testing methods and varying the test speed, the rubber content and temperature. Specific attention at the modifications of brittle/ductile transition [4] changing these parameters has been placed, studying analytical models to predict them. References [1] Coltelli M.B., Bronco S., Chinea C. “The effect of free radical reactions on structure and properties of poly(lactic acid) (PLA) based blends” Polymer Degradation and Stability 95, (2010), 332-341 [2] Lazzeri A., Bucknall C.B., “Dilatational bands in rubber-toughened polymers” Journal of materials science (1993) 28, 6799 [3] Al Itry, R., Lamnawar, K. and Maazouz, A. “Improvement of Thermal Stability, Rheological and Mechanical Properties of PLA, PBAT and Their Blends by Reactive Extrusion with Func-tionalized Epoxy”. Polymer Degradation and Stability, 97, (2012), 1898-1914 [4] Mai Y.W., Cotterell B. “On the essential work of ductile fracture in polymers” International Journal of Fracture 32, (1986), 105-125