Background: Medical laboratory service is very essential for sustainable and reliable patientrndiagnosis and treatment. Interruption is a global problem and much higher in resource limitedrnsettings. However, there is no adequate evidence on the magnitude and contributed factors.rnThus, this study aimed to assess the laboratory service interruption and its associated factorsrnin public hospitals found in Addis Ababa, Ethiopia. rnMethods: Facility based cross sectional study design was conducted in public hospitals foundrnin Addis Ababa using qualitative and quantitative data from April-June/ 2020in Ethiopia.rnStandardized check list was developed to assess level of interruption and also structuredrndichotomous questioners’ were used for related factors. Data was entered and analyzed usingrnSPSS version 23. Binary and multiple logistic regression analysis were used to explanatoryrnfactor that affect the outcome variable. rnResult: Totally 190 laboratory professionals were participated with a response rate of 95.5%.rnIn public hospitals averagely 17(23%) tests were interrupted for 76(84%) days. In specializedrnand General hospitals averagely 13(17%) and 19(28%) tests were interrupted, respectively. Inrnthis study serology and hematology tests accounts the highest level of interruption which isrn5(6.9%) and 4(5.5%) respectively. While parasitological, urinalysis and body fluid analysisrnwere consistently available. Absence of laboratory annual plan at [AOR=3.028, pvalue=0.044,rn95%Clrn(1.030-8.903],rninappropriaternequipmentrnmaintenancernrnat [AOR=9.350, pvalue=0.003,rn95%Clrn(2.102-41.596],rnandrnshortagernofrnreagentsrnandrnsuppliesrnatrn[AOR=3.845,rnpvalue=0.049,rnrn95%Cl (1.008-14.663] were the major factors that affect laboratory servicerninterruption. rnConclusion: Even though sustainable laboratory service is important in the health carernservice, most public hospital laboratories found in Addis Ababa did not provide continuousrndiagnostic service for all expected tests. Therefore, to improve service interruption, hospitalrnmanagers, health professionals and other stakeholders should undertake effort to intervene thernfactors that affect laboratory service interruption.