PURPOSE: To report rates of and reasons for operation cancellation, and to prioritize areas of improvement. METHODS: Retrospective data were extracted from the monthly reports of cancelled listed operations. Data on 14 theatres were collected by the office of quality assurance at Jordan University Hospital from August 2012 to April 2016. Rates and reasons for operation cancellation were investigated. A Pareto chart was constructed to identify the reasons of highest priority. RESULTS: During the period of study, 6,431 cases (9.31%) were cancelled out of 69,066 listed cases. Patient no-shows accounted for 62.52% of cancellations. A Pareto analysis showed that around 80% of the known reasons for cancellation after admission were due to a lack of surgical theatre time (30%), incomplete preoperative assessment (21%), upper respiratory tract infection (19%), and high blood pressure (13%). CONCLUSION: This study identified the most common reasons for operation cancellation at a teaching hospital. Potential avoidable root causes and recommended interventions were suggested accordingly. Future research, available resources, hospital policies, and strategic measures directed to tackle these reasons should take priority.