Osteoarthritis (OA) is the most common arthritic condition, which is one of the leading causes of disability in adults. Currently, no treatment can stop or reverse the progressive joint degeneration caused by OA. Most clinical interventions aim to improve pain and physical function. Transcutaneous electrical nerve stimulation (TENS) is widely used in the management of knee OA to relieve osteoarthritic pain and facilitate the performance of therapeutic activities in order to maintain or improve physical function. Although its use is widespread, the available evidence is of questionable quality. An adequately sized and well conducted randomized controlled trial (RCT) investigating the effectiveness and safety of TENS as treatment modality for knee OA is warranted to assist clinicians and policy makers to make decisions that are based on high-quality evidence, ultimately optimizing delivery of health-care in knee OA.