At this time there is an increasing demand for an accurate pre operative staging in non small cell lung cancer. Chest Computed Tomography (CT) is one of the imaging modality of choice used for this purpose. This study evaluated the accuracy of the chest CT to determine the status of tumor and nodules in non small cell lung cancer. During the years 1998 and 1999 a descriptive prospective study of 32 patients undergoing a contact enhanced chest CT examination for non small cell lung cancer, stage I-IIIA, was conducted. Lobectomy, lu\ymph nodes dissection and postoperatice histo-pathological examination were done. CT findings were as followas a sensitivity of 100% , a specificity of 25% and an accuracy of 60% in the detection of the nodule stage were found. In 17 patients with adeno-carcinoma, the sensitivity, the specificity and the accuracy were 86.6%, 100% dan 88.2% respectively. The diagnosis of all patients was conformed histo-pathologically. Six patients with T2 dan 26 patients with T3 were detected by chest CT; the accuracy of the tumor status was 93.7% confirmed by surgical and histo-pathological examinations. It was concluded that th CT played an important role in determining the clinical stage of non small cell lung cancer. The specificity and accuracy were higher in adeno-carcinoma as compare with squamous cell carcinoma in detecting the nodal status.