An enquiry into the use of antibiotic prophylaxis in conjunction with diagnostic or therapeutic urological procedures at hospitals in four Scandinavian countries showed manifest national differences to exist for most procedures. In transurethral resection, for instance, antibiotic cover was used at 79 percent of Finnish hospitals, but at only nine percent of Danish hospitals. Not only were dosage regimens characterized by wide national variation, but also the spectrum of antibiotics used, quinolones being most frequently used in Sweden, but ampicillin and pivampicillin in Denmark. For some procedures policy was more uniform in all countries, antibiotic cover rarely being used in connection with ureterocystoscopy (5 percent of hospitals), but often in conjunction with percutaneous stone surgery (72 per cent). In certain procedures where there is strong evidence suggesting the necessity of antibiotic prophylaxis, it was not always used-e.g., in transrectal prostate biopsy where it was used at only 62 per cent of hospitals. The interpretation of published findings and clinical experience would appear to differ markedly, and local traditions would seem to be strong determinants of clinical routines. The wide variation suggests that all patients do not receive optimal treatment. To improve routines, our knowledge of antibiotic preparations needs to be expanded by well executed studies, followed by general implementation of the results at the various centres. A series of consensus conferences should be arranged and the recommendations published as a first step toward a more uniform and probably better use of antibiotic prophylaxis in conjunction with diagnostic and therapeutic urological procedures.