Prolongation of the corrected QT (QTc) interval is associated with various anaesthetic drugs. The QTc prolongation may become more exacerbated during laryngoscopy and intubation, which is possibly caused by sympathetic stimulation. The aim of this study was to investigate the effects of fentanyl on the QTc interval during propofol induction in healthy patients. The patients were randomly allocated to receive either fentanyl (n = 25) or saline (n = 25) before induction. The QTc interval was significantly prolonged immediately after intubation in control group compared to preceding values, but it did not change in the fentanyl group. The number of patients with the prolonged QTc interval exceeding 20 ms immediately after intubation compared to the baseline values was 14 in the control group and seven in the fentanyl group. In conclusion, pretreatment with fentanyl 2 microg x kg(-1) significantly attenuated QTc prolongation associated with laryngoscopy and tracheal intubation during propofol induction.