[en] Seismic isolation is at the present time in a very active state of development. Many new types of isolation systems are being explored and elastomeric isolators, the system which has been employed on almost all isolation systems completed to date, continue to undergo improvements. At least one dozen large projects, either new or the retrofit of existing buildings, have been completed and design studies are underway for at least another one dozen large projects. A large experimental research project for isolators with nuclear reactor application has been carried out over the past few years at EERC. This program has involved shake table testing and the testing of full-scale and model isolators. A wide variety of isolators have been tested including low-shape factor, moderate-shape factor, and very high-shape factor elastomer bearings. The range of elastomers that have been tested include low-damping, high-damping, and very low-modulus compounds. Full-size and model isolators have been tested to failure in several failure modes and the safety margins for isolation systems have been established. The test results have shown that properly designed and manufactured isolators for nuclear reactor applications can sustain levels of loading beyond any possible seismic input and demonstrate that failure of an isolation system cannot occur before failure of the isolated structure. Thus, the use of isolation can only have beneficial contributions to the protection of nuclear facilities, internal piping, and equipment. The presentation will review the latest developments in the implementation of base isolation and describe the results of the test program for its application to nuclear facilities. (author)