A 35-year-old man with the acquired immunodeficiency syndrome (AIDS) presented with a multitude of constitutional symptoms, fever, and marked intrathoracic lymphadenopathy. Results of initial diagnostic examination were unrevealing, and bronchoscopy with fine-gauge flexible transbronchial needle aspiration (TBNA) of subcarinal lymph nodes was performed. Two aspirates were obtained, one for cytologic study and the other for acid-fast smear. Despite obtaining acid-fast smears from numerous sites, only TBNA provided evidence of acid-fast organisms and prompted early antimycobacterial therapy. We believe this is the first report of mycobacterial intrathoracic lymphadenopathy diagnosed by TBNA.