Diabetes is a rapidly growing disease, with important complications that decrease the quality of life of patients. Diabetic Foot Ulceration is a major complication of diabetes and can lead to gangrene and amputation. It is related to high pressure developed on the plantar surface and can be prevented and treated with pressure offloading footwear. Current solutions are either mechanic insoles and shoes or smart devices that perform only plantar pressure measurements. This paper presents the design of a device that performs pressure offloading using magnetorheological fluids. The device consists of a magnetorheological valve that controls the offloading and a force sensor. An electronic board is used for force measurements and control of the valve. The experimental results validate the offloading capabilities of the device. Due to their size, multiple such devices, and the electronic board, can be integrated into diabetic footwear to achieve active offloading.