Abstract Pain and accompanying symptoms of primary dysmenorrhea, a condition defined by cramping-associated pain during menstruation without identifiable pelvic pathology, are a true disturbance to daily activities and quality of life. High prevalence of dysmenorrhea translates to over 855 million people suffering from this condition worldwide. Severe symptoms of dysmenorrhea force up to 33% to miss school or work, resulting in 600 million hours missed annually and an annual economic burden of over $2 billion in the U.S. Non-steroidal anti- inflammatory drugs (NSAIDs) and hormonal contraception (HC) are the first-line options for treating dysmenorrhea, but with 20-25% of people not responding to NSAIDs and many finding the side effects of NSAID and HC use to be unacceptable, the overall effectiveness of these therapies is limited. Thus, there remains an urgent unmet medical need worldwide to develop a safe, effective, and accessible therapy for dysmenorrhea. Recent clinical studies have shown that acupuncture-based nerve stimulation of a specific peripheral nerve can be effective for treating dysmenorrhea symptoms. While promising for reducing pain and distress, acupuncture’s low acceptability to patients and the need for scheduled care at the clinic prevent its potential widespread use for dysmenorrhea treatment. To build on this work and address the need for a comprehensive therapy for dysmenorrhea, TheraNova has developed the SoleStim Neuromodulation System, a portable, non-invasive ,Plantar Neuromodulation (PNM) device for non-invasive stimulation of peripheral nerves. The SoleStim Neuromodulation System consists of standard, inexpensive gel electrodes and a small, battery-powered signal generator. The goal of this proposal is to conduct a pilot clinical study to evaluate the potential of SoleStim as a treatment for dysmenorrhea. We will conduct a 16-week, sham-controlled study in 33 participants with primary dysmenorrhea. Treatment effectiveness will be evaluated via participant-reported daily pain scores and standard dysmenorrhea surveys. For the first 8 weeks (Baseline Phase), participants will self-report on dysmenorrhea symptoms to establish baseline values. Then, participants will be randomized (1:1) to the active or sham treatment and self-administer daily treatment at home for the duration of the 8-week Treatment Phase while also providing self-reports on dysmenorrhea symptoms. In this single study, we will evaluate metrics of feasibility (Specific Aim 1) and acceptability (Specific Aim 2). After demonstrating feasibility in Phase I, we will conduct a long-term pivotal clinical trial in Phase II to support FDA clearance and enable commercialization after Phase II.