This paper sets out to audit infectious morbidity before and after introduction of a policy of antibiotic prophylaxis following emergency and elective caesarean section in a district general hospital in Scotland with approximately 3800 deliveries a year. In the first 'loop of audit', case notes of 200 consecutive patients managed during 1992 were studied. Audit loop was completed by studying 224 patients prospectively in 1993-94 following the introduction of new guidelines, which required the intraoperative administration of a single dose of intravenous antibiotic, following delivery of the baby. A significantly greater proportion of women received prophylactic antibiotics in 1993 compared with 1992 (81% vs. 14%; Diff= 67%; 95% CI 60%, 74%). The incidence of infection related morbidity was significantly reduced after routine antibiotic prophylaxis (28,5% vs. 16%; Diff= 12.5%, 95% CI=(4.60%,20.4%). The incidence of wound infection was halved in 1993 (9% vs. 17.5% in 1992). None of the patients in 1993 had a serious postoperative infection. Postnatal stay was significantly shorter in 1993 compared with 1992 (P < 0.0001). Although the target of adherence to the guidelines of 90% coverage was not met, this audit demonstrates the benefits of antibiotic prophylaxis for emergency and elective caesarean sections. Further reduction in morbidity may be obtained by strictly implementing the guidelines, and also by considering the use of multiple doses of antibiotics.