Background: Cancellation of surgical operations on the proposed day is a significant problem worldwide, and this forms the major issue for the ineffective utilization of the operations room including all staff who contribute in the cancelled operations as physicians and other medical professionals. Despite that, the quality of any health care services can be measured by the cancellation rates of elective surgeries. Methods: retrospective cross-sectional study for 10262 cases were collected from a tertiary medical hospital in which the surgery was cancelled, starting from January 2015 and ending in December 2019, these cases were taken without selecting a specific specialization or type of operation. Data analysis done according to the age, gender, responsible side, and the reason and type of the Cancellation. Results: About 10262 of medical records were selected and reviewed from January 2015 till December 2019 at a Tertiary medical hospital in Riyadh. This study showed that more than half of surgery cancellations from different departments were mostly caused by surgeons (56.5%), while (36%) were caused by admission offices, and (7.4%) were by other departments. The highest rate of cancellations was in 2018, while lowest was in 2019. The most common reasons for Cancellation were non-admitted patient (32.4%), medical reasons (24.9%), and booking-related reasons (18.2%), however, other findings showed that most of the cancellation reasons were patient-related (60.9%), administrative or booking related (21.2%), and facility or staff related (17.5%). Conclusion: In order to minimize surgical operations cancellation, we strongly recommend creating a pre-admission unit and occupying it with competent nurses who are capable of raising patients' awareness, assess their co-morbidities, absorbing their worries and anxiety, and improving their satisfaction. Keywords: Operation cancellation, elective surgery, tertiary medical hospital, elective surgery, Riyadh