Background: Sinonasal disease affects a wide range of population including broad spectrum ofrndiseases both inflammatory conditions, congenital and neoplastic. Since their clinical assessmentrnis fraught by the surrounding bony structures; diagnostic radiology is of paramount importance.rnThis study is aimed at assessing the CT patterns of sinonasal pathologies which is the first studyrnto the best of our knowledge at Tikur Anbessa Specialized Hospital and in Ethiopia. rnObjective: To assess computerized tomography patterns of sinonasal pathologies and patternsrnof histopathologic findings at Tikur Anbessa Specialized Hospital. rnMethods: Institutional based retrospective cross-sectional study was carried out at TikurrnAnbessa Specialized Hospital department of radiology. A non-probability convenience samplingrntechnique was employed to include all patients imaged at radiology department for sinonasalrndiseases during the study period. Data was collected from medical record books and imagingrnarchive system to see the imaging reports of patientsâ€™ images from November 2019 â€“ July 2021,rnusing structured data extraction template. The date was collected from June to August 2021. Datarnwas entered and analyzed using SPSS 26 statistical software. Ethical clearance was obtainedrnfrom Ethical Review Committee of the Department of Radiology at Addis Ababa University. rnResult: A total of 102 patients were included during the study period of which 64(62.7% werernmales and 38(37.3%) were females with age range of 1 day up to 83 yrs. The mean age was 30.7rn+ 20.9 years and median age 27.5 years. The most common presentations were nasal dischargern52(50.9 %), and nasal blockage accounting 42(41.2%) Inflammatory etiology is the mostrncommon finding accounting 47.1% (N=48) of the cases and malignant masses is the second mostrncommon category which accounted 28(27.4 %) of the cases. From those having histology thernmajority are malignant 25(71.4% N=35). rnConclusion: In this study malignant sinonasal pathologies are common next to inflammatoryrncauses. All choanal atresia cases were bilateral. Further prospective study with large number ofrnparticipants is recommended as this institutional based retrospective study in tertiary center mayrnnot represent the general population.