We experienced a case of right median nerve palsy at the distal forearm following abdominal surgery. We postulate that the cause of the median nerve palsy is overextension of the wrist by the inappropriate fixation with a holder. The patient was a 46-year-old man with habit of smoking receiving low-anterior resection of the rectum under general and epidural anesthesia in lithotomy position. During surgery his upper limbs were placed on padded arm board abducted about 80 degrees and affixed with soft cotton. His forearms were slightly supinated, whereas his elbows were not over-extended. A 22 G cannula was inserted in the right radial artery and the right wrist was fixed with plastic-holder with soft pad. This position was maintained throughout the operation approximetly for 250 minutes. During anesthesia any special events regarding hemodynamic variables were not observed. He complained of numbness in the palmar side of the digits 1-3 on his right hand without motor disturbance 4 hours after the operation. Examination by the anesthesiologist revealed median nerve palsy. Fortunately, this symptom gradually but completely resolved over the next few days. The possible causes of this neuropathy include the overextension of the wrist or the unexpected extension of the elbow beyond the acceptable range by the supination of forearm, which was induced by the attachment used to stabilize an intra-arterial catheter. Therefore, in the current case we should have returned the wrists promptly to the neutral position following arterial catheter placement to prevent the median nerve palsy. This case suggests the importance of holding the proper position of the arm during surgery.