Magnetorheological elastomer (MRE) is a new branch of MR materials, which are smart materials whose rheological properties can be controlled by the application of an external magnetic field. MREs are solid, rubber-like materials whose modulus can be adjusted by applying magnetic field. In this article, the current research and patents on the material fabrication, modeling and testing, and applications will be reviewed and discussed. As the articles review, recent interesting in applications focused on three main areas. The first one is on the sound and vibration control, especially on the vehicle applications, including dynamic vibration absorber and isolator. The second one is on the controllable stiffness change and deformation, such as roll in papermaking machine and releasable fastener system. The third one is on the sensors and actuators. In summary, MREs have made significant advances and will have promising applications.