OBJECTIVE: To investigate factors altering the manifestation and outcome of pulmonary tuberculosis (PTB). DESIGN: The medical records of culture- proven TB patients from July 2001 through December 2002 were reviewed. RESULTS: A total of 461 patients were identified. Diabetes (21.5%) and malignancy (15.2%) were the most common underlying comorbidities. Sixteen cancer patients were initially misdiagnosed as pulmonary metastasis or recurrence. Younger patients frequently had constitutional symptoms and haemoptysis, while older patients frequently had respiratory symptoms and pleural effusion. Male predominance was noted, except in the 21–40-year- old non-diabetic group. Diabetic patients were more likely to present with cavitary nodules. Lower lung field TB was noted in 96 (20.8%) patients, and was associated with female sex and consolidative pattern. Factors associated with poor prognosis included underlying malignancy, chronic renal failure, serum albumin