There are several studies suggesting decreased operating room efficiency caused by cancellations of the surgical procedures. It also affects patient satisfaction. This study was to analyse the reasons for cancellation of elective operations so that in future necessary actions can be taken to minimize number of unnecessary cancellations. METHODS: This was a retrospective study conducted in teaching hospital for 3 years from April 1, 2012 to March 31, 2015. The data was collected from postponement register and medical record department. The reasons for cancellations were classified as (1) structural factors (e.g., no hospital bed); (2) patient factors (e.g., patient unwell); and (3) process factors (e.g., scheduling error). RESULTS: During the study period, 11,208 patients were posted for elective procedures. 9.8 % patients were cancelled on the day of surgery. The frequency of cancellations was more in process related issues (47.9%). Cancellations due to structural factors and patient factors were 26.4% and 25.7% respectively. CONCLUSION: Although cancellations were only 9.8% of total elective operations, this can be reduced by anticipating and taking necessary steps that have been suggested. More thorough and detailed documentation is needed to achieve this.