The diagnosis of tuberculosis in patients with negative acid-fast bacillus smears poses a challenge to both clinicians and public health authorities. In an attempt to aid diagnosis in such cases, an expert committee was established in Ciudad de La Habana, Cuba in 1995. The aim of this study was to describe the progress of the committee's work and the corresponding results for the period 1996 through 2003. For each patient studied by the commission, we analyzed the following data: patient's residence and referring center, tentative diagnosis proposed by the attending physician, history of antibiotic treatment, and final diagnosis made by the commission. Of the 1703 patients studied, 84.8% were from La Habana, 48.4% were 55 years or older, and 63.8% were men. Between 2001 and 2003, 11.3% of patients were already on antituberculosis treatment when their case was studied by the commission. The corresponding percentage for 1996 through 2000 was 16.9% (P=.001). Active tuberculosis was confirmed in 43.1% of a total of 918 patients with full test results during the period 1996 through 2000 and in 52.2% of a total of 619 patients (52.2%) during the period 2001 through 2003 (P< .001). Of 344 patients with suspected pulmonary tuberculosis and negative acid-fast bacillus smears between 2001 and 2003, 128 (37.2%) were diagnosed with active tuberculosis. These findings indicate that the work of the commission is viable, sustainable, and useful for preventing overdiagnosis and inappropriate treatment, and that it also serves an educational purpose.