SETTING: A community-based treatment program for multidrug-resistant tuberculosis (MDR-TB) in Lima, Peru. OBJECTIVES: To describe the activities carried out by the nurses working with the program. DESIGN: A qualitative study using a variety of ethnographic methods, including participant observation, focus groups, and key informant interviews over a 5-year period. RESULTS: Nurses were responsible for carrying out a wide variety of activities within the program. These included patient-focused activities such as identifying patients, evaluating patients prior to starting and during therapy, and managing emergencies; educational activities for both patients and health professionals managing MDR-TB; and coordination activities, including overseeing health workers and communicating between team members. CONCLUSION: Nurses play a key role in the community-based management of MDR-TB.