Magnetorheological (MR) fluids are materials that consist of dispersions of ferromagnetic particles in a liquid carrier medium. Their tunable rheological properties under the application of an external magnetic field classify them in the category of smart materials. These properties are exploited for the creation of magnetorheological valves that act as actuators, dampers or shock absorbers. In this work, the optimal design of a miniature radial magnetorheological valve is presented. The target use of the valve is a wearable medical application, thus, constraints emerge regarding its size, pressure drop and power consumption. The optimization process relies on the Design of Experiments (DoE) techniques and the Response Surface Method (RSM). The optimal model is compared with the results of previous studies on different valve configurations.