Background: A well-organized Laboratory Quality Assurance Program includes InternalrnQuality Control (IQC) procedures, External Quality Assessment (EQA) programs andrnLaboratory Quality Management (LQM). IQC is a set of procedures that are used in daily routinernwork to control daily variance of test results, problems are identified immediately and thernmethod is brought back on track. So it needs professionalsâ€˜ knowledge and commitment. Internalrnquality control (IQC) in laboratory is a crucial part of quality processes.so that poor practices ofrnprofessional on IQC affect the result of patients. That is why this study raises the question ofrnKAP of laboratory professionals in use of IQC among selected public and private hospitals inrnAddis Ababa. rnObjective: To assess knowledge, Attitude and Practice of clinical laboratory proffessionals andrnassociated factors in use of IQC for laboratory tests among selected public and private Hospitalrnin Addis Ababa, Ethiopia. rnMethods: A cross sectional study was conducted using questionnaire to assess KAP ofrnlaboratory professionals and its associated factors in use of IQC among selected public andrnprivate hospitals in Addis Ababa from February 2020 to April 2020.A total of 250 laboratoryrnprofessionals from selected public and private Hospitals were participated in the study. Pre-testedrnand self-administered questionnaire were used .Data entry and analysis were performed by usingrnSPSS version 20 software. Descriptive statistics, such as mean, median, analysis were used.rnAssociation of different factors with KAP of laboratory professionals were done using the Binaryrnlogistic regression and level of statistical significance was set at p