The treatment of tuberculosis (TB) is ranked as the most cost effective of all therapeutic programmes in terms of cost per year of life saved. Nevertheless, TB kills or debilitates more adults aged between 15 and 59 years than any other disease in the world; furthermore, about 2 to 4% of the burden of disease, 7% of all deaths and 26% of all preventable deaths are directly attributable to TB. About one-third of the world's population is infected with the TB bacillus. In the developing world, more women of childbearing age die from TB than from causes directly associated with pregnancy and childbirth. The death of adults in their prime, who are parents, community leaders and producers in most societies, causes a particularly onerous burden besides being a serious public health problem. In the poorest countries, where the magnitude of the TB problem is greatest, those TB control strategies that are economically feasible tend to be less effective. Therefore, in low and middle income countries, cost-effectiveness considerations aimed at prioritising resource allocation in the health sector in general, and in TB control programmes in particular, are of paramount importance. Operationally, the main components of a TB control programme are: (i) detection and treatment of TB; and (ii) prevention of TB through BCG vaccination and chemoprophylaxis. Priority should be given to ensuring that TB patients complete their prescribed course of chemotherapy. Adequate treatment is the most effective way of preventing the spread of TB and the emergence of drug resistance. This article reviews evidence of the effectiveness and cost effectiveness of different approaches to TB care, particularly those that are applicable to low income countries, in both HIV-infected and noninfected patients. Financial implications and ways to implement directly observed therapy for TB in large urban areas are discussed, and the need to address some relevant operational issues is highlighted. The current role of chemoprophylaxis and BCG vaccination is also reviewed.