Bacterial growth in relation to suction drains and suction drain tubes following total hip replacements was studied in 105 consecutive patients. All the patients were operated on in a Charnley Howorth Mark II sterile enclosure without walls, but with a body exhaust system and routine antimicrobial prophylaxis. Specimens for culture were taken from the suction drain tip, from inside the suction tube and the incision site. Positive cultures were found in a7 patients; in 20 of them from either the drain tip or the drain track. In 15 patients, the culture revealed coa-gulase-negative staphylococci; in 12 of them from the drain tip or the drain track. Eight patients had a positive culture from the tip of the drain and 16 from the drain track. Four patients had signs of wound hematoma and serous discharge. No patient developed signs of deep infection during the first 12 months after surgery. This study confirms that coagulase-negative staphylococci are the most common single species obtained from cultures after total hip replacement. Routine antimicrobial prophylaxis against coagulase-negative staphylococci might be considered.