OBJECTIVE The prognosis in patients with pulmonary tuberculosis and acute respiratory failure requiring mechanical ventilation is believed to be poor. The aim of this study was to identify factors contributing to in-hospital mortality in these patients. METHODS The medical records of 32 patients with active pulmonary tuberculosis as a primary cause of acute respiratory failure requiring mechanical ventilation in the medical intensive care unit (ICU) of a tertiary referral hospital over a 10-year period were reviewed retrospectively, and predictors of mortality were assessed. RESULTS The patients' median age was 69 years (range 25-88 years). The median length of intensive care unit stay was 11 days (range 2-88 days), and the median duration of mechanical ventilation was 9 days (range 2-86 days). Overall in-hospital mortality was 59% (19/32). Independent predictive factors of in-hospital mortality included tuberculous-destroyed lungs (hazard ratio 6.61, 95% CI: 1.21-36.04, P = 0.029), Acute Physiology and Chronic Health Evaluation II scores > or =20 (hazard ratio 4.90, 95% CI: 1.43-16.80, P = 0.012) and sepsis (hazard ratio 5.84, 95% CI: 1.63-20.95, P = 0.007). CONCLUSIONS Acute respiratory failure caused by pulmonary tuberculosis necessitating mechanical ventilation has a high mortality rate and poor prognosis, particularly in patients with tuberculous-destroyed lungs, high Acute Physiology and Chronic Health Evaluation II scores and sepsis.