The incidence of active tuberculosis among inmates of New York State prisons increased from 15/100,000 in 1976-1978 to 139/100,000 in 1993. By comparison, the rate in the general population of New York State in 1993 was 22/100,000. Overcrowding in prisons and the prevalence of immune-suppressed inmates infected with HIV contributed to the increasing incidence of tuberculosis. These high rates of tuberculosis infection and disease among inmates have raised concern about transmission to prison employees. This report used results of 2 years of tuberculin skin testing to determine if work in specific job categories, or work in a prison in which inmates were diagnosed with active tuberculosis in 1992, were risk factors for converting from negative to positive on the test. Approximately 33 percent of new infections in 1992 among all New York State prison employees were due to occupational exposure. This attributable fraction of new cases varied by job category and depending on whether an employee was working in a prison which had inmate cases. Tables, references