The utility of antibiotic and mechanical preparation for colorectal surgery is controversial, and numerous different regimens are used. The aim of this study was to detect trends in preparation for surgery among American colon and rectal surgeons. Members of the American Society of Colon and Rectal Surgeons practicing in the United States were surveyed with a postal questionnaire regarding their routine preparations for colon and rectal surgery. Five hundred fifteen (40%) of the 1295 questionnaires sent were returned. Eighty-one per cent of the respondents had completed an accredited colorectal training program, and the average experience in practice was 13.7 (+/- 8.7) years. Half of the surgeons felt that prophylactic oral antibiotic is essential, 41 per cent felt it was doubtful, and 10 per cent considered oral prophylaxis unnecessary. Despite these statements 75 per cent of the surgeons routinely utilized oral antibiotics (96% of them used a combination of two drugs), 11 per cent used them selectively, and only 13 per cent omitted oral prophylaxis from their practice. Similarly although the usefulness of intravenous antibiotics was questioned by 11 per cent of the surgeons 98 per cent routinely used them. The average number of postoperative doses was two (+/- 1.9). Although 10 per cent of the surgeons questioned the importance of mechanical preparation more than 99 per cent routinely used it. Forty-seven per cent of the surgeons used sodium phosphate, 32 per cent used polyethylene glycol, and 14 per cent alternated between these two options. We conclude that although the use of oral antibiotic prophylaxis for colorectal surgery is controversial among surgeons it is still routinely practiced by 75 per cent. Intravenous antibiotic prophylaxis and mechanical cleansing, however, are still a dogma and almost invariably used. There is a trend toward the use of a shorter course of postoperative intravenous antibiotics and the use of sodium phosphate for mechanical cleansing.