Shape memory foams were developed based on LLNL shape memory polymers (SMPs). These urethane foams were based on hexamethylene diisocyanate (HDI), triethanolamine (TEA), and N,N,N’,N’,-tetrakis(2-hydroxypropyl)ethylenediamine (HPED), and produced by a combination of chemical (H20) and physical blowing.  The resulting foams have a predominantly open cell structure, densities ranging from ca. 0.1 to 0.015 g/cc, glass transitions from less than 34 to 121 ºC, and volume expansibilities (Vf/Vo) of up to 80 times.  Such materials are expected to have a number of potential applications ranging from expandable components for aerospace to aneurysm filling implants. In this paper we discuss the development of the process for making these materials, their physical properties, and their mechanical properties related to use in an endovascularly delivered implant for stabilizing cerebral aneurysms.   For example, in compression and recovery testing expansion stresses measured for the foams drop below 1 kPa at recovery strains higher than 50%, at least 2 orders of magnitude below expected rupture stresses for the aneurysm wall.  This data strongly suggests that the SMP foams can expand to fill and stabilize aneurysms without further expanding their size or causing rupture.