Tuberculosis (TB) is an occupational disease of healthcare workers (HCWs). Administrative and engineering interventions simultaneously implemented in hospitals of developed countries have reduced the risk of nosocomial transmission of M. tuberculosis. We studied the impact of administrative infection control measures on the risk for latent TB infection (LTBI) among HCWs in a resource-limited, high-burden country. An intervention study was undertaken in a university-affiliated, inner-city hospital in Rio de Janeiro, where routine serial tuberculin skin testing (TST) is offered to all HCWs. From October 1998 to February 2001, the following infection control measures were progressively implemented: isolation of TB suspects and confirmed TB inpatients, quick turnaround for acid-fast bacilli sputum tests and HCW education in use of protective respirators. Among 1336 initially tested HCWs, 599 were retested. The number of TST conversions per 1000 person-months during and after the implementation of these measures was reduced from 5.8/1000 to 3.7/1000 person-months (P=0.006). The most significant reductions were observed in the intensive care unit (from 20.2 to 4.5, P<0.001) and clinical wards (from 10.3 to 6.0, P<0.001). Physicians and nurses had the highest reductions (from 7.6 to 0, P<0.001; from 9.9 to 5.8, P=0.001, respectively). We conclude that administrative measures for infection control can significantly reduce LTBI among HCWs in high-burden countries and should be implemented even when resources are not available for engineering infection control measures.