Areas of potential contamination of the surgical wound in the conventional operating rooms include the back table, the unsterile suction receptacle, and the lack of a positive pressure relationship between the operating room and adjacent areas. Use of an impermeable hood with a large mask diminished contamination of the instrument table and the the wound from fallout of bacteria from the surgical team. The level of airborne bacterial comtamination in the operating room can be reduced by limiting the traffic and controlling the activity and the number of operating room personnel. Higher rates of postoperatively wound sepsis were noted in older operating rooms, particularly with difficult procedures and those performed later in the day. Conventional operating rooms should be categorized by the level of room air exchange per hour and the level of airborne bacterial contamination.