Background & Objectives: Since 1985 because of increasing incidence of tuberculosis (TB) in HIV background, the outbreaks of TB have been reported in different parts of the world. From 1985 to 1991 the incidence of TB increased by 18% in United States and Europe. In Multi Drug Resistant outbreaks of TB in United States 18 to 35% of heath care workers (HCW) who had exposure to TB patients had PPD Converted to positive test (Seroconversion). That is why the risk of TB incidence in health care workers has been put forward again. This study was designed to determine the rate of Buali hospital HCW exposure to mycobacterium tuberculosis.

 Methods: All 96 HCW of Buali hospital took part in this cross-sectional and analytical study. No PPD test was performed for HCW in this hospital in the beginning of their employment. For this reason 30 officers who had not previously worked in hospital wards and 60 medical students who had not started their clinical course were selected to obtain an estimation of PPD test before starting professional nursing.

  Results: Out of 96 subjects, 72 were female and 24 were male. Rate of positive PPD was 50% in general. Data analysis showed that PPD positivity was in direct relationship with number of working years in hospital. In 60 university students whose mean age was 21.6± 0/2.9 PPD positivity rate was 13.3%. I the third group consisting of 30 office workers (mean age=333±6.5) it was 23.3%.

 Conclusion: This study shows that HCW with 50% of PPD positivity are in exceeding probability of mycobacterium tuberculosis exposure, which is almost twice as much as the other office workers, possibility of exposure.