The paper discusses the use of rubber bearings in base isolated structures. In Japan alone there are likely to be 100 base-isolated buildings completed by the end of 1994 all of which will be on rubber bearings [Ref 1.2]. A distinction is drawn between the use of rubber bearings in bridges where they are subject to both the fatigue of traffic loading and diurnal temperature movements throughout their life, and their use in buildings where the loading is comparatively static until severe earthquake shaking occurs, which at a particular location is not likely to occur more than about once a century. Vertical load capacity and characteristics of vertical deflection in relation to rubber layer thickness and instability are discussed. Shear stiffness and deflection characteristics are outlined together with methods used for providing damping, including damping in lead-rubber bearings. The design of the high-stability aseismic bearing for loads of 1 tonne upwards is discussed in relation to its stability characteristics. It is suggested that tensile forces should be permitted in the short-term loading induced by earthquakes and this is confirmed by current Japanese practice in using fully bonded bearings. The development of self-damping rubber bearings is discussed.