The right paratracheal stripe (RPS) is a band-like water density between air-column of the trachea and the surrounding right lung. The authers have experienced some unexpected diseases and earlier diagnosis made by the right paratracheal stripe, therefore, this study was done to determine the normal range of RPS in Korean by measuring of RPS in 132 normal subjects, 30 pregnant women and 120 pathologic cases. The results obtained are summerized as follows; 1. The normal limit of RPS in Korean was 1-4mm, and it is reguared as abnormal finding when the RPS value exceeds the normal limits. 2. It was less than 2.5mm in 80% of normal adult, and 60% was in between 1.6 to 2.5mm. 3. The RPS of pregnant women was within normal limits, and it was the same tendency in pneumonic subjects. 4. The RPS was increased with the order of pleurisy, primary and metastatic lung cancer, pulmonary tuberculosis subjects.