Tuberculosis (TB) is a communicable disease spread by tiny airborne particles that are expelled when a person with the disease coughs or sneezes. Botswana has had one of the highest TB notification rates in the world since 2000, mainly as a result of increasing rate of HIV prevalence in the country. People at a high risk of contracting TB are close contacts to a person who already has the disease. It is therefore important that after being diagnosed with TB, all close contacts of the affected patient are traced and interviewed to decide whether they need to be tested for the disease or not, so as to combat the spread of TB. This paper explores the issues involved in the design of a mobile phone-based application for TB contact tracing in Botswana. Problems with the current paper-based method are discussed, and a design and architecture of a mobile phone-based Unstructured Supplementary Service Data (USSD) platform is presented.