The overall objective of this study is to determine if active tuberculosis (TB) case finding among persons residing in the same household as a person with active pulmonary TB (household contact investigation) is an effective TB control intervention in a low-income setting with a high incidence of TB and a high prevalence of HIV infection. Specifically, in this project I will determine the feasibility, and measure the impact and costeffectiveness of training former patients to conduct household TB contact investigation and household HIV testing in Dar es Salaam, Tanzania, a setting with a high incidence of TB and HIV. The study will focus on the households of patients with infectious pulmonary TB; the pilot assessing the feasibility of household HIV testing will focus on newly diagnosed TB and HIV cases. I will seek to determine whether household contact investigation results in earlier diagnosis and an increased yield of previously unidentified active TB cases and whether both interventions are feasible and cost-effective. The translation of these findings into practice will fill a gap in the evidence base that is necessary for policy formulation.