This paper assesses the impact of economic studies on TB control during the period 1982–2002, with a focus on cost and cost-effectiveness studies. It begins by identifying broad categories of economic study relevant to TB control, and how economic studies can, theoretically, have an impact on TB control. The impact that economic studies of TB control have had in practice is then analysed through a systematic review of the literature on cost and cost-effectiveness studies related to TB control, and three case studies (one cost study and two cost-effectiveness studies). The results show that in the past 20 years, 66 cost-effectiveness studies and 31 cost studies have been done on a variety of important TB control topics, with a marked increase occurring after 1994. In terms of numbers, these studies have had most potential for impact in industrialized countries, and within industrialized countries are most likely to have had an impact on policy and practice related to screening and preventive therapy. In developing countries with a high burden of tuberculosis, far fewer studies have been undertaken. Here, the main impact of economic studies has been influencing policy and practice on the use of short-course chemotherapy, justifying the implementation of community-based care in Africa, and helping to mobilize funding for TB control based on the argument that short-course treatment for TB is one of the most cost-effective health interventions available. For the future, cost and cost-effectiveness studies will continue to be relevant, as will other types of economic study.