A prospective randomised study was conducted in three centres to evaluate the efficacy of teicoplanin as antimicrobial prophylaxis for arthroplasties. From a total of 616 patients undergoing total hip or knee arthroplasty, 278 patients operated on in one centre were administered a single dose of 10mg/kg teicoplanin upon introduction of anaesthesia and the remaining 338 patients operated on in the other two centres were administered multiple doses of comparators for 4-6 days as decided by the attending physicians. Follow-up was done for 24 months. No differences were found between the two groups regarding gender, underlying diseases and duration of the operation. Surgical site infections (SSIs) were present in two patients in the teicoplanin arm (0.78%) and in 11 patients in the comparator arm (3.53%) (P=0.025 between groups). These were deep SSIs in four patients (two in each arm). Two cases of severe allergic reaction occurred, one in the teicoplanin arm and another in the comparator arm. It is concluded that single-dose teicoplanin was more effective as prophylaxis for total hip or knee arthroplasty compared with multiple doses of broad-spectrum antimicrobials.