Aim: In this study, we aimed to evaluate CT findings of those hila that are thought to be enlarged on chest X-rays. Material and Method: We reviewed contrast-enhanced thoracic CT scans of 1000 patients (653 males/347 females) admitted to the hospital with various pulmonary complaints. We included CT scans into this study if the requesting physician mentioned that CT examination should evaluate the hilar enlargement seen on chest X-ray. We evaluated both hila on CT regarding the diameter of pulmonary arteries and the size of hilar lymph nodes if exist. A right pulmonary artery diameter larger than 20 mm and a left pulmonary artery diameter larger than 22 mm were considered as vascular dilatation. A hilar lymph node with a short axis diameter equal or greater than 11 mm was noted as lymphadenomegaly. Results: Thoracic CT findings were abnormal in 412 (41.2%) patients. Vascular dilatation was the most common etiology of hilar enlargement at 24.8%. Excluding vascular dilatations, thoracic CT findings were abnormal in 16.4% of the patients. After diagnostic work-up, a definitive diagnosis was reached in 51 patients (5.1%). Interstitial lung disease (n=28) and lung cancer (n=16) were the most common diagnoses. Discussion: A contrast-enhanced thoracic CT is the best way to determine the etiology of hilar enlargement. In this study, the ratio of abnormal findings (vascular dilatations, lymphadenopathy, lymphadenopathy and vascular dilatation, mass) was 41.2%. We think that this ratio was high enough to justify the request of thoracic CT by the physicians.