Rationale, aims and objectives A range of strategies have been proposed to identify and address operating theatre delays, including preoperative checklists, post-delay audits and staff education. These strategies provide a useful starting point in addressing delay, but their effectiveness can be increased through more detailed consideration of sources of surgical delay. Method A qualitative, observational study was conducted at two Australian hospitals, one a metropolitan site and the other a regional hospital. Thirty surgeries were observed involving general, vascular and orthopaedic procedures which ranged in time from 20 minutes to almost 4 hours. Approximately 40 hours of observations were conducted in total. Results The research findings suggest that there are two key challenges involved in addressing operating theatre delays: unanticipated problems in the clinical condition of patients, and the capacity of surgeons to regulate their own time. These challenges create unavoidable delays due to the contingencies of surgical work and competing demands on surgeons' time. The results also found that surgical staff play a critical role in averting and anticipating delays. Differences in professional authority are significant in influencing how operating theatre time is managed. Conclusions Strategies aimed at addressing operating theatre delays are unlikely to achieve their desired aims without a more detailed understanding of medical decision making and work practices, and the intra- as well as inter-professional hierarchies underpinning them. While the nature of surgical work poses some challenges for measures designed to address delays, it is also necessary to focus on surgical practice in devising workable solutions.