Pleural tuberculosis effusion (PTE) in children is a diagnosis which must be considered in isolated pleural effusions in non-toxemic children. It is more common in children over 5 years of age. A history of close contact with an adult with pulmonary tuberculosis reinforces the suspicion for its diagnosis. Pleural effusion without any parenchymal lesion is the characteristic finding on the chest x-ray. However, in 20% to 40% of patients, intrathoracic disease may also occur. Adenosine deaminase, interferon-gamma, analysis of pleural fluid and pleural biopsy are the main tools for diagnostic confirmation. Tuberculin skin test may provide supporting evidence of tuberculous infection. PTE has a good prognosis in children and no long term sequelae are expected.