A 21-year-old morbidly obese parturient with a body mass index of 45.5 kg x m(-2) underwent an emergent cesarean section for obstructed labor under combined spinal and epidural anesthesia. At age 15, she was diagnosed as borderline personality disorder. In spite of the drug therapy, her mental status was unstable. During anesthesia and surgery, her psychiatrist attended beside her to ease her anxiety and mental stress. An experienced anesthesiologist encouraged her and maintained her in the sitting position during epidural catheterization and spinal puncture. The distance between the skin and the epidural space was about 6.5 cm at the L3-4 interspace via midline approach. An epidural catheter was inserted 5 cm cephalad. Subsequently, the L4-5 subarachnoid space was accessed at a depth of about 7.0 cm. A 3 ml bolus of 0.5% hyperbaric bupivacaine was given. The anesthetic level was T4 at the start of the operation. Throughout the surgery, sufficient analgesia was obtained and any complication such as severe hypotension or respiratory depression did not develop and her postoperative course was uneventful.