The results of computed chest tomograms (CT) and chest roentgenograms (CR) were compared in 32 patients who presented with hemoptysis. The CT demonstrated roentgenographic abnormalities more often than CR (p less than 0.01), providing new diagnostic information in 15 patients (46.9 percent), and clarifying CR abnormalities in five (15.6 percent) others. In addition, CT correctly localized sources of bleeding in 23 (88.5 percent) of the 26 patients in whom a site was identified at bronchoscopy, while CR localization was correct in 17 (65.4 percent) (p less than 0.05). Despite this augmentation of roentgenographic yield, information derived from CT scans influenced the management of only six patients, did not obviate the need for bronchoscopy, and supplemented the combined diagnostic yield of CR and bronchoscopy in only two. Outcome was changed in one patient in whom CT had demonstrated an otherwise unrecognized malignant solitary pulmonary nodule. The chest roentgenogram and fiberoptic bronchoscopy provided all the information essential for diagnosis and therapeutic recommendations in 93.7 percent of these patients. Although the CT provided additional information in over one half of our patients, its overall impact on clinical management was small and does not support routine use of this imaging procedure in evaluation of hemoptysis. The possible role of chest CT in evaluating carefully selected patients with hemoptysis requires further study.