Shape-memory polymers (SMP) are a new class of smart materials which possess the ability to recover a “programmed” permanent shape from a temporary one, when submitted to an external stimulus. We have already demonstrated the remarkable shape memory properties of extruded starch materials, stimulated by temperature or surrounding humidity. The shape recovery is induced by the relaxation of residual stress when ambient conditions induces the glass-rubber transition. The macromolecular organization has been characterized by wide angle X-ray scattering on constrained (temporary shape) and relaxed samples (permanent shape). WAXS diagrams present a broad amorphous scattering band. The azimuthal integration of the scattering intensity on constrained samples exhibit periodic scattering intensity changes with maximum parallel to the length of the specimen. This demonstrates that the amorphous structure is oriented in the direction of the mechanical deformation applied at the rubbery state and fixed during the cooling of the sample. The macromolecular orientation remains stable below Tg and probably originates from the residual stress stored in the glassy samples. Macromolecular conformation was characterized by synchrotron radiation polarized infra red microspectroscopy. This allowed to confirm the presence of orientation as detected by WAXS but at a much higher resolution (12 μm). It shows that amorphous domains are mainly involved in the shape memory effect but also that some ordered domains are present within the samples. The presence of infrared sharp bands linked to hydrogen bonds and a (1-4) linkage evidence the presence of local order which could be under the form of helical fragments potentially stabilized by intramolecular H bonds. All the results obtained about mechanical properties and amorphous organization are discussed using the concept of flexible and rigid domains present in shape memory polymers. The oriented / disoriented amorphous organization of starch seems associated to the flexible domains, the transition being triggered by Tg. The nature of rigid domains is still unclear. It could be entanglements or nanometric local order, called paracrystallinity.