In patients with acquired immunodeficiency syndrome (AIDS)-associated pulmonary Mycobacterium tuberculosis (MTB) (group 1), we analyzed whether the addition of transbronchial biopsy (TBB) and bronchial brushings augmented the diagnostic MTB yield over nonbiopsy sampling. Positive acid-fast bacilli (AFB) smears from combined sputum, bronchoalveolar lavage (BAL), and washings were 30 percent compared with 37 percent when brushings and TBB were added (p = NS). The addition of TBB increased culture yield from 96 percent to 100 percent (p = NS). Similar results were seen in patients with pulmonary MTB without human immunodeficiency virus (HIV) risk factors (group 2). Group 1 patients most commonly had a nonspecific inflammation on TBB histopathology and had a lower incidence of granuloma formation than group 2 (p less than 0.05). Our results suggest that more invasive sampling with bronchial brushings and TBB does not contribute to the microscopic, bacteriologic, or histopathologic diagnosis of pulmonary MTB, independent of AIDS risk factors.