The administration of isoniazid (INH) has been proposed, evaluated and implemented to prevent tuberculosis (TB) disease among patients who are infected with the human immunodeficiency virus (HIV). This strategy has been developed in communities where TB is highly endemic and at a time when antiretroviral (ARV) treatment was not, or was rarely available. Although INH prevention programmes were somewhat pushed to the background due to the worldwide advocacy for ARV drugs, prevention of TB remains of paramount importance. The dual HIV–TB infection poses problems, not only for the individual and his/her clinician but also for the programme manager. We review various aspects of TB preventive treatment in countries with a high prevalence of HIV–TB co-infection and limited resources but with increasing access to ARV treatment.