The caesarean section rate in the UK has more than doubled during the last two decades and is continuing to rise. The majority of studies carried out to determine the incidence of infection associated with this procedure have been restricted to the inpatient stay, which may give misleading results. Women undergoing caesarean section have routine contact with a community midwife after discharge. This provided an opportunity to assess whether a collaborative surveillance approach between hospital and community staff was feasible using routinely available information. Following a successful pilot study, 11 maternity units in the East Midlands participated in an extended study. Complete records were available for 5,563 (88%) women. Overall, 758 (13.6%) wound problems were reported, 84% of which developed after discharge. Of these, 488 (8.9%) met national definitions for surgical site infection (SSI); however, there was a marked inter-unit difference in incidence, ranging from 2.9% to 17.9%. Statistical models were used to examine these differences using 12 possible risk factors. Five risk factors were found to be significantly associated with the development of a surgical site infection: body mass index, age, blood loss, method of wound closure and emergency procedures. These results suggest that caesarean section is associated with high infectious morbidity, the extent of which would have been considerably underestimated without post-discharge monitoring. Almost all women with wound problems were treated with antibiotics, regardless of how minor the problem, with 97% being prescribed in the community. This indicates a requirement for local review of antibiotic prescribing practice.