A 31-yr male with insulin dependent diabetes mellitus for 20 years underwent general anaesthesia for renal transplantation. During transfer from operating theatre to ICU he developed bradycardia advancing to ventricular fibrillation and had to be resuscitated. Bradycardia did not respond to atropine. Postoperative autonomic nervous function tests showed advanced autonomic neuropathy. He was found to have constantly prolonged QTc interval in his pre- and postoperative ECGs (462-503 ms). Prolongation of QTc interval could be used as a valuable predictor of postoperative cardiac complications in diabetic patients with autonomic neuropathy.