Because pulmonary metastases in patients with primary neoplasms have both therapeutic prognostic implications, a review was undertaken of 100 patients with primary neoplasms in whom whole lung tomography and chest roentgenography had been performed. Eight (20%) of 28 patients with solitary metastases on conventional films had more than one lesion on tomography. Due to the tomographic findings, therapy was altered in six of those eight. Two (3%) of 72 patients with normal chest roentgenograms had metastases visible on their tomograms. The data indicate the high value of whole lung tomography in determining therapy whenever a solitary metastasis is visible on conventional chest roentgenograms. The 3% pickup rate of metastases in patients with normal chest roentgenograms is less clear-cut but does suggest the contribution tomography can make in patients with potentially curable lesions.