The Index case, 22 year-old pregnant woman, was admitted for threatened abortion among obstetric ward in X Hospital for 17 days. Two months later, she was admitted for delivery among perinatal ward in another Y Hospital for 5 days. She produced persistent cough and sputum, when she had diagnosed pulmonary tuberculosis (TB) with sputum smear-positive and cavity on 2nd Y hospital day. By 2 years after the detection, 15 TB patients were newly diagnosed. Seven of 15 TB patients were culture positive cases and RFLP analysis of the 7 Mycobacterium TB strains demonstrated an identical banding pattern, thus confirming the spread of a unique strain. Of the 15 TB patients, seven were patients on the obstetric ward. Three were visitors. Two were infants with TB meningitis and miliary TB were not confirmed direct contact with the index case. Another two were family member and one was employee. The present outbreak emphasizes the high risk of TB transmission on obstetric and perinatal ward when the diagnosis of smear-positive pulmonary TB was delayed.