The term 'transcutaneous electrical nerve stimulation' (TENS) is synonymous with a standard TENS device. Increasingly, nonstandard TENS-like devices are being marketed to health care professionals for pain relief. These include: interferential current therapy, microcurrent electrical therapy, high-voltage pulsed (galvanic) currents, TENS-pens, transcranial electrical stimulation and Limoge currents, Codetron, transcutaneous spinal electroanalgesia, action potential simulation, and H-wave therapy. This review evaluates the effectiveness of TENS and TENS-like devices for pain relief, to inform health care professionals about device selection. The results from systematic reviews suggest that TENS is not effective for postoperative pain and labour pain, although volatile evaluation models may partly explain the ndings. Evidence is inconclusive for chronic pain. Health care professionals should not dismiss the use of TENS for any condition until the issues in clinical trial design and review methodology have been resolved. There is limited experimental evidence available for most TENS-like devices. Claims by manufacturers about the speci city and extent of effects produced using TENS-like devices are overstated and could probably be achieved by using a standard TENS device or a microcurrent electrical therapy device. When making decisions about device selection, health care professionals should consider the physiological intention of currents and whether this can be achieved by using particular devices. Clinical trials that examine the relative effectiveness of TENS-like devices with a standard TENS device are desperately needed.