Antituberculous chemoprophylaxis with isoniazide during a period of one year is very useful although it is not readily accepted. A community trial is designed in order to test if three health education interventions increase patients compliance with such treatment in case of tuberculin positive children who are not ill. The two interventions performed by nurses, one by phone, and the second one by a home visit, resulted in statistically significant difference when compared to the control group. This did not occur, however, with the intervention performed by the doctor in his office. A cost-effectiveness study demonstrates that the most efficient intervention has been the phone call.