Abstract-In this paper presents the design and development of a portable prototype of a neuromuscular electrical stimulation and iontophoresis offering a rehabilitation therapy in patients with knee osteoarthritis, an disease that affects the largest adult population worldwide and interferes in quality of life for people who have it. The implemented therapy aims to act on pain fibers and produce analgesia and welfare; likewise stimulate the tissues involved in the mobility and biomechanics to the knee for preventing deterioration of the elements and articular atrophy, increasing tissues metabolism, in order to retard articular cartilage deterioration and thus disease. The hardware is based on an Android application that connects to the computer through the bluetooth communication; the application can store information related to the patient and configure and register therapies from Smartphone. The pacing system was coupled to a knee orthosis that allows placing electrodes for superficial treatment, this orthosis is suitable for both right and left limb. The prototype was designed under the technical standards related to the electrical safety of assets medical equipment and specifically the standard for design and construction of nerve and muscle electrostimulation equipment (NTC 60601-2-10).