The authors retrospectively analyzed high resoluton(HR) CT scans of the brain in 23 patients with surgically proved primary lung cancer and intracranial metastatic lesions from April 1986 to March 1990. The purpose of this study was to evaluate the relationship between histopthologic types of primary lung cancer and HRCT findings of brain. The locations of metastatic lesion were intraaxial in 93% and extraaxial in 7%. In the intraaxial lesions, most were in the supratentorial area(83%) and the remainer in the infratentorial area(10%). Among the supratentorial lesions, the parietal lobe was the most commonly involved(33%), while the second most common location was frontal lobe(22%). The HRCT showed multiple lesion in 52% and solitary lesions in 48%. All cell types except for squamous cell carcinoma showed the same incidence in multiplicity, and the squamous cell carcinoma showed slightly more multiple lesions rather than solitary ones. The degree of peritumoral edema was none in 4%, mild in 25%, moderate in 46%, and severe in 25%. All cell types except for squamous cell carcinoma in general showed a moderate degree of edema, and squamous cell carcinoma mainly showed mild and severe edama. Precontrast CT scans showed mixed density in 52%, isodensity in 24%, low density in 19%, and high density in 5%. All cell types except for large cell carcinoma showed mixed density, the large cell carcinoma showed a low density unlike the others. Hemorrhages were seen in 24% and noted in all cell types except for large cell carcinoma. Postcontrast CT scans showed ring enhancement in 64%, nodular enhancement in 20%, and inhomogeneous enhancement in 16%. All cell types except for small cell carcinoma generally showed ring enhancement, and the small cell carcinoma showed a variable degree of enhancement.