The utility of routine admission chest roentgenograms (CXRs) was evaluated in detecting pulmonary tuberculosis and the relationship between roentgenographic patterns and the likelihood of finding acid-fast bacilli (AFB) on sputum smear. Of 58 patients whose chief complaints were unrelated to pulmonary tuberculosis, the CXR suggested tuberculosis in 52 cases (90 percent). In 45 cases, the emergency room physician failed to elicit the patient's respiratory symptoms and did not consider tuberculosis as a diagnostic possibility. In 18 individuals, the diagnosis was missed in the emergency room because of failure to obtain a CXR. Among patients whose roentgenograms showed cavitation or extensive alveolar infiltrate, sputum smears showed AFB in 98 percent of cases. If alveolar infiltrate was absent, or if the roentgenographic pattern was not that of adult reactivation disease, sputum smears revealed AFB in only one half of the cases. We conclude that routine admission CXRs are useful in hospitals serving populations where tuberculosis is still common, and the probability of detecting AFB on sputum smear is greatly influenced by the roentgenographic findings.