Background: Day of surgery cancelation is elective surgical procedure that is not performed on thernplanned day of surgery despite being on the finalized operating room schedule, for any reason. Dayrnof Surgery cancellation is a well-recognized quality problem and reflects inefficiency in managementrnof operating room time, manpower and hospital resources and one of the sensitive quality indicatorsrnin perioperative care. Cancelation prevalence, major causes of cancellations, costs of surgicalrnprocedure cancelation vary across countries, regions and hospitals. Point prevalence varies fromrn1.83% to 40%. Reasons for cancellations are complex because they are related to patients,rnorganizational issues, and clinical situations Cancellation of scheduled elective operations decreasesrntheatre efficiency and is inconvenient to the patients, their families and the medical teamsrnObjectives: To assess the prevalence and causes day of surgery cancellation and suggest solutions forrnbetter patient management and effective utilization of resource in TASH.rnMethods: This was hospital based prospective observational cross sectional study conductedin allrnmajor operation rooms from June 1st to June 31 2019 GC. At TASH.the study subject were allrnpatients, of all ages, both genders, who were scheduled for elective surgicalrnoperationsfromsurgicalspecialties (Cardiothoracic, General, Neuro, pediatric, orthopedic, Uro, Gyne,rnobstetric) scheduled to undergo elective surgical operation.rnResults: A total of 380patients were scheduled for elective surgeries during the study period, 266rnpatients had their operation performed at the scheduled time whereas 114(30%)patients wererncancelled at the day of surgery in which 68.4% were potentially avoidable. The most common causesrnfor cancellations were surgeon related accounts for 56 cases (49.1%) followed by administratorrelatedrnreasons, 41 (36% lowest was anesthesia related 3(2.6). lack of operating time due tornpreceding long operation/unanticipated complication, overscheduling, surgeon not availablerncomprise about 70% of surgeon related cause whereaslack of OR material(36.6%), ICU bed(14.6%)rnand mechanical ventilator(22%) were major cause of administrative related causes patient changedrnmind after overnight fasting(35.7%) and acute change in medical condition(28.5%) were commonrnpatient related factorsover all 68.4%(78/114) of cancellation was avoidable. The highest percentagernof cancellation related to the scheduled operations was in the NS 55.1% followed by CT andrnorthopedics (53.3%, 34.4%) while the lowest was Gyne and urology (15%, 14.9%) respectively .Mostrncommon cause of cancellation for NS and ortho was administrator 48% /5o% respectively followedrnby surgeon related (NS, 37%) causes whereas in CT surgeon related was the commonest (75%)rnConclusions:Rate of cancelation is high in our setup which wastes the already limited resourcesrnbecause most of causes are preventable each of the stake holders should take responsibility andrnstrive to decrease DOS cancelation. General understanding, communication and cooperationrnbetween the surgical, anesthesiology, nursing, patient and logistic team will reducing the incidence trna minimum and increase the efficacy of the hospital. Audit carried out at regular intervals to find outrnthe effective functioning of the OR and thorough assessment of feasibility and profitability ofrnapproaches that have been proven to be successful in other institutions, in the context of ourrninstitution characteristics and individual problems and taking proper administrative measures willrndecrease cancelation and its attendant adverse events.