BackgroundTuberculosis (TB) in elderly is a worldwide problem. ObjectiveTo evaluate differences in clinical, radiological, laboratory features, adverse antituberculosis drug reactions and TB-related mortality in elderly and young pulmonary TB patients. ResultsThe study included analysis of the medical history, chest radiographic and laboratory findings in 124 elderly and 124 young pulmonary TB patients, with mean age of 60.5±9.1 and 31.6±10.8years, respectively (p<0.0001), and comparable male predominance. There were higher frequencies of dyspnea, anorexia, weight loss, weakness and mental changes in elderly than young (p= 0.001, 0.004, <0.0001, <0.0001, 0.002, respectively) while there were higher frequencies of cough and sputum production, hemoptysis, and fever in young than elderly (p= 0.008, 0.01, 0.04, respectively) patients. Elderly had higher frequency of comorbidities (p<0.0001). Elderly had higher frequency of atypical radiological findings for pulmonary tuberculosis and initial misdiagnosis as pneumonia and lung cancer (p<0.0001, 0.001, 0.01, respectively). Elderly had a higher level of erythrocytic sedimentation rate (p=.01). Young had a higher frequency of positive sputum direct smear for acid fast bacilli (p=0.04). Elderly had a higher role for fiberoptic bronchoscope in diagnosis of pulmonary TB (p=0.001). There was a delay in the diagnosis of pulmonary TB in elderly (p<0.0001) patients. Anti-tuberculosis drug side effects and TB-related mortality were more frequent in elderly (p<0.0001, 0.03, respectively)patients. ConclusionThis study showed that elderly pulmonary TB patients had higher frequencies of atypically clinical, radiological presentations, co-morbidities, anti-tuberculosis drug adverse reactions and TB related mortality.