Tuberculosis (TB) in health care workers (HCWs) was not considered a serious problem following the advent of effective antibiotic therapy. Interest was re-stimulated by the occurrence of several major nosocomial outbreaks. We have reviewed the available published literature regarding prevalence and incidence of TB infection and disease among HCWs in countries categorised by mean income. We included studies published in English since 1960 from low- and middle-income countries (LMICs) and since 1990 from high-income countries (HICs). We excluded outbreak reports and studies based only on questionnaires. The median prevalence of latent TB infection (LTBI) in HCWs was 63% (range 33-79%) in LMICs and 24% in HICs (4-46%). Among HCWs from LMICs, LTBI was consistently associated with markers of occupational exposure, but in HICs it was more often associated with non-occupational factors. The median annual incidence of TB infection attributable to health care work was 5.8% (range 0-11%) in LMICs and 1.1% (0.2-12%) in HICs. Rates of active TB in HCWs were consistently higher than in the general population in all countries, although findings were variable in HICs. Administrative infection control measures had a modest impact in LMICs, yet seemed the most effective in HICs. TB remains a very important occupational risk for HCWs in LMICs and for workers in some institutions in HICs. Risk appears particularly high when there is increased exposure combined with inadequate infection control measures.