Introduction:Ca-125 is secreted by different celomic epitheliums. Serum levels may be increased in malignant diseases, like ovarian cancer but also in other medical conditions, such as pulmonary and extrapulmonary tuberculosis.Methods:From Jan-04 to Dec-06 a retrospective study analyzing Ca-125 levels in serum samples from patients with a diagnosis of pulmonary TB, was performed. These results were compared with those samples obtained from patients with non-TB pulmonary infections.Results:Eighty-nine patients were included in the study, thirty-five with pulmonary TB and 54 with other respiratory infections. In patients with TB, the mean Ca-125 value was 104.9 IU/ml (SD: ± 136.1). In the control group, mean value was 27.1 IU/ml (SD: ±19.7). The optimal cut-off for pulmonary tuberculosis was 32.5 IU/ml (sensitivity: 68.6%, specificity: 77.8%). Pulmonary TB was the only factor associated with a Ca-125 level >32.5. In 10 patients with TB, Ca-125 levels were available ≥ 2 months after starting TB therapy and a decrease during treatment was shown.Conclusions:Ca-125 values increase in patients with pulmonary TB and decline to normal values during treatment. Determination of Ca 125 may be usedin patients with a negative sputum AFB stain.