Background: Spinal anesthesia is the preferred anesthesia technique employed in a variety ofrnsurgical procedures. Even though it is safe and reliable technique, the occurrence of failed spinal rnanesthesia (FSA) may not possibly avoided. Sometimes the failure may have a seriousrnconsequence. Study reports on incidence of failed spinal anesthesia vary among countries .Somernpractitioners assert that an incidence rate of less than one present is attainable. In Ethiopia,rnalthough spinal anesthesia is widely used in a variety of surgical procedure, and failure is observedrnin a day to day practice, the incidence and associated factors of failed spinal anesthesia is not yetrnknown. In order to minimize the risk of failure, the incidence and the associated factors have to bernidentified. rnObjective: To investigate the incidence and associated factors of failed spinal anesthesia inrnadults who underwent elective surgery in public hospitals at Addis Ababa, Ethiopia. rnMethods: An institutional based cross sectional survey was conducted on 266 eligible adultrnelective surgical patients from January 31rnstrn to April 30rnthrn, 2021 at selected public hospitals, AddisrnAbaba, Ethiopia. Systematic random sampling method was employed for selecting samples. Datarnwas entered and analyzed with SPSS version 24. Binary and multivariable logistic regressionrnanalysis was done to access significance of factors associated with failed spinal anesthesia. Atrn95% conï¬dence interval a p-value of less than 0.05 was considered as statistically signiï¬cant. rnBoth crude and adjusted odds ratio were calculated to show strength of association. rnResults rnThe incidence of FSA among the adult who underwent elective surgery under SA was 21.01%rn(54/257). In multivariable analysis experience of anesthesia provider of service years less than tworn(AOR=3.556; 95% CI=1.832-6.905), Bloody CSF (AOR=2.738; 95% CI=1.365-5.491) andrnnumber of spinal attempt greater than two, (AOR=2.919, 95% CI =1.458 â€“5.846) werernsignificantly associated with failed spinal anesthesia. rnConclusion and Recommendation: The results of this study reveal that the incidence ofrnfailed spinal anesthesia at Addis Ababa public hospitals, Ethiopia, is high compared to the results rnof studies done in other countries. Associated factors identified as significant predictors for failedrnspinal anesthesia in this study were more of avoidable factors. Hence, first, the anesthesiarnproviders needs to be aware of the high incidence and then they should make the best possiblerneffort to minimize failure by giving due attention to detail at each steps of the technique duringrnprocedures. Furthermore, the findings of this study and developments, if any, need to be reviewedrnwith subsequent similar studies.