Introduction: - Triage is sorting of patients according to their clinical need and the availabilityrnof resource. It is important for resource limited setting in which the volume of patients visitingrnto hospital is unpredicted. Even though the triage tool is important to sort the right patient to thernright place at the right time, some patients seen not triaged and evaluated properly as observedrnand evidenced from many literature. So, this study identifies whether the tool is properly filled,rnthe parameters correctly measured and recorded, patients are well categorized and evaluated atrngiven time frame and the factors affecting its implementation. rnObjectives: - To assess triage implementation and factors affecting it among patients visitedrnTikur Anbessa Specialized Hospital Adult Emergency Department, Jan.2016 to Jan.2018. AddisrnAbaba, Ethiopia. rnMethodology: - Institutional based cross sectional study was conducted at Tikur AnbessarnSpecialized Hospital Adult Emergency Department by selecting the patients chart using simplernrandom sampling and reviewing it which was visited and triaged in the past two years.rnDescriptive statistics was used to compute individual variables, regression for associated variablernand Odds ratio at 95% CI to show strength of association. rnResult: - From the total eligible sample 43.7% were incorrectly triaged. Among them 25.22%rn(n=29) were over triaged while 74.78% (n=86) were under triage. Correct TEWS scorerncalculation for triage (AOR=3.019, 95% CI {1.139, 8.005, P=0.026), adult age grouprn(AOR=3.018, 95% CI {1.357, 6.712}, P=0.007) and use of clinical discriminator (AOR=8.582,rn95% CI {1.873, 17.389} P= 0.000) were the factors significantly associated with triage ofrnpatients. The use of clinical discriminator increase over triage proportion by 3.4 foldrn(AOR=2.400, 95% CI {2.095, 5.515}, P=0.000). rnConclusion and recommendation: - Close to half of the patients are not triaged in proper wayrnin adult emergency. Thus, those patients are not getting adequate and efficient care since they arernnot allocated in their respective area. Periodic monitoring and evaluation, training and awarenessrncreation and allocation of materials is needed to solve the problem.