Bacteriologic data and aspiration smears obtained by fine needle aspiration (FNA) biopsy for a series of 39 cases of tuberculosis were reviewed. Based on the morphologic features of the aspiration smears, the cases were divided into two groups: 18 cases in which distinct epithelioid granulomas were present and 21 in which no granulomas were found but large amounts of necrotic debris with variable numbers of polymorphonuclear cells, histiocytes and lymphocytes were present. Material from the FNA biopsy specimen was submitted for culture and fluorescence studies in 34 cases (15 with and 19 without granulomas). In the first group, auramine-rhodamine staining of smears was positive in 4 of 15 cases and Mycobacterium tuberculosis was isolated in 12 of 15 cases. In the second group, auramine-rhodamine staining was positive in 9 of 19 cases and culture was positive for M. tuberculosis in 16 of 19 cases. The results indicate that studying FNA smears by light microscopy and bacteriologic culture is an effective way of diagnosing tuberculosis.