This is a descriptive report of a pilot project of tuberculosis (TB) treatment in a conflict zone. A TB programme was implemented by Médecins Sans Frontières(MSF)-Holland in a semi-nomadic population in a very insecure and underdeveloped area of Upper Nile province in Southern Sudan. Outcome measures were operational feasibility, default rate, and sputum smear conversion at 4 months. A cohort of TB patients was admitted over a 10-week period (July-September 2001). Adherence strategy, project implementation, and and contingency planning were adapted to local conditions. The treatment regimen (4 HRZE [4-month daily supervised regimen] followed by 3EH or 3TH [3-month unsupervised regimen]: isoniazid (H), rifampicin (R), pyrazinamide (Z), ethambutol (E) and thiacetazone (T)) was a variant on the Manyatta regimen developed for semi-nomads in Kenya. Of 163 patients, 84 (52%) were children aged < 15 years. Lymph node TB comprised 34% and spinal TB 15% of all patients. Among adults, 41% had smear-positive pulmonary disease. Only 1 patient (0.6%) defaulted. All sputum smear-positive patients who completed 4 months of therapy converted to smear-negative, although 2 were subsequently found to have relapsed. TB in complex emergency situations is an underrecognized priority. Using an approach adapted especially to this setting, TB treatment was successfully implemented with minimal risk of promoting drug resistance, in an unstable setting.