Transcutaneous electrical nerve stimulation (TENS) has been used in a variety of acute and chronic painful conditions, but has not been studied in sickle cell pain crises. We compared TENS versus placebo in a randomized, double-blind, cross-over study involving 60 trials in 4 crisis severity categories. TENS electrodes were applied to the area of severest pain and patients' pain ratings and medication usage were evaluated over a 4-hour period. Pain ratings and analgesic requirements at 1 and 4 h from onset of study were similar in the TENS and placebo groups. Patients assessments of overall treatment efficacy indicated that TENS was more frequently helpful, but there was a substantial placebo effect. Although the value of TENS in this condition was not established in this study, further trials, using varied stimulation parameters, are warranted.