Tuberculosis immunization status was assessed in 2,501 individuals seeking employment in a district general hospital between January 1979 and December 1981. For 587 (23 per cent) of the employment seekers there was no evidence of BCG vaccination and nor were any of them aware of having had a tuberculin skin test at school. Tuberculin skin tests (Heaf's test) on these 587 individuals showed no reaction in 163 (28 per cent) and a strong (grade 4) reaction in 50 individuals. Only five of the individuals with grade 4 reaction to Heaf's test needed chemotherapy. During the same period, 43 patients with tuberculosis were in contact with 1,568 members of the hospitals's staff.The management of occupational contact is described and the need to rescreen the population at risk is discussed.