The incidence of contamination of epidural catheters used for pain control was investigated. To prevent epidural infection, all patients with epidural catheters had taken amoxacillin 1.5gm/day orally. Of the cultures of catheters catched from 303 patients undergoing continuous epidrual catheterization, 5 catheters (1.7%) were found to be contaminated; cervical 1/86 (1.2%), thoracic 1/27 (3.7%), and lumbar 3/190 (1.6%). Staphylococcus epidermidis was the most common etiologic agent (60%). To prevent epidural infection, sterilization of the skin around the epidural catheter and prophylactic use of broad-spectrum antibiotics are thought to be beneficial.