Objective To assess the value of transcutaneous electrical nerve stimulation (TENS) during cervical laser therapy. Design Randomized three arm controlled clinical trial comparing (i) TENS, (ii) local anaesthetic and (iii) TENS plus local anaesthetic (direct infiltration of 2% lignocaine and 0.03 iu/ml octopressin). Setting Colposcopy Unit adapted to run randomized trials. Subjects 100 women with CIN and no previous experience of cervical surgery. Main outcome measure Visual linear analogue pain scores. Results The median pain score associated with TENS was greater than the score associated with local anaesthesia (23% compared with 17%; P= 0.1). Combining TENS with local anaesthesia did not further reduce pain scores. Conclusion Although there was considerable consumer satisfaction with TENS it provided no additional pain relieving effect in addition to direct infiltration of lignocaine and it is inferior to lignocaine alone. We are unable to advocate the use of TENS for laser treatment of the cervix.