One hundred ten hospitalized patients with hemoptysis were reviewed to identify factors that would characterize those with malignancy and to evaluate the usefulness of fiberoptic bronchoscopy (FB) in the diagnosis of hemoptysis. Seventy patients underwent FB. This procedure was diagnostic in 22/28 (79 percent) of the carcinoma patients and in 26/42 (62 percent) of the patients with a nonmalignant cause of hemoptysis. The following three characteristics indicate a high probability of malignancy: 1) age greater than 40 years, 2) any abnormality on the chest roentgenogram, 3) hemoptysis lasting greater than one week. If any of these factors are present, FB should be done. Other factors to be considered include presence of anemia, weight loss, persistent cough, long smoking history and risk of bronchoscopic complications.