After having ascertained their relevance, epidemiologic indicators of tuberculosis infection were calculated in the area of coverage of a district hospital. For this purpose, a tuberculinic survey was undertaken among students of 2nd. and 8th. grade (EGB) and among those of 1st. grade during two consecutive courses. A prevalence of 2.08% (+/- 1.08%) in 1st. grade (in 1986-87), of 1.18% (+/- 0.87%) in 1st. grade (in 1987-88), of 1.13% (+/- 0.79%) in 2nd. grade (in 1987-88) and of 2.19% (+/- 1.10%) in 8th grade (in 1987-88). The annual incidence of infection in the studied period was 0. The Annual Risk of Infection (ARI) was lower than 0.12% with an annual reduction of 57%. This is the first time that indicators of infection are obtained in a population of the region of Valencia, and are compared with other populations. We outline the benefits of the investigation of the source of infection and of the family contacts. Fourty-eight Mantoux (+) children were detected, of which 8 had tuberculosis, 1 had residual lesions, and the remaining ones were at the infectious stage. Among the 105 studied adults, 60 were Mantoux (+), of which 6 had tuberculosis, 2 of them were smear (+) and 5 had residual lesions. Chemoprophylaxis was initiated in 14 cases.