Medical error is an important cause of morbidity and mortality. Organisational failure in the pre-operative period has been associated with catastrophic outcome. Little information is available regarding peri-operative organisational problems. The incidence and nature of organisational failure before urgent and emergency surgery in a district general hospital was studied prospectively in 159 cases over a 30-day period. Organisational failure affected more than half of the cases overall, but varied in both its incidence and its complexity between surgical disciplines. Various causative factors were identified, e.g. 8% of cases were subject to delay due to clinical emergencies. The median [range] time required to rectify the problems was 115 [5-750] min. A consultant anaesthetist and surgeon were present in 30 and 20% of cases, respectively. Difficulty with the preparation of patients for emergency surgery is an important but underevaluated cause of medical error that may put patients at risk.