Abstract: The present contribution reviews some recent electron microscopy investigations on different shape memory systems in which a variety of nano- and micro-defect structures play an essential role in the functional behaviour of the material. (NiTi3)-Ti-4 precipitates in Ni-Ti are a well-known example for which the focus is now on the 3D configurations, in Ni-Ti-Nb Nb-rich nanoprecipitates are thought to have a large impact on the hysteresis, in Co-Ni-Al an Al-enriched zone nearby the y'-precipitates yields a small sandwiched austenite while some first signs of quasidynamical lattice deformation in non-frozen Ni-Ti strain glass are measured by Cs-aberration-corrected transmission electron microscopy. (C) 2011 Elsevier B.V. All rights reserved.