An environmentally degradable composition comprises blends of a physical mixture of a poly(lactic acid), comprising about 1 to 99 weight percent of the composition, and an elastomeric blend compatible polymer, such as a segmented polyester, that provides improved impact resistance to the poly(lactic acid) and is discrete and intimately bound; plasticizer is added to the blend that is selected from the group consisting of lactide monomer, lactic acid oligomer, lactic acid, and mixtures thereof. Other plasticizer that may be added includes one or more derivatives of an oligomer of lactic acid, its esters and copolymer.