To exclude tuberculosis, WHO/UNAIDS recommends considering medical history, symptom screen, and chest radiograph before starting tuberculosis prevention in people infected with HIV. The value of a chest radiograph for this purpose is unknown. We prospectively assessed 935 HIV-infected outpatients seeking isoniazid preventive therapy. Of 935 patients, 692 (74%) had no signs or symptoms of tuberculosis. Of these 692, 123 (18%) were lost during the chest radiograph process, and one (0.2%) of the remaining 563 was diagnosed with tuberculosis on the basis of the chest radiograph. A screening chest radiograph should not be required routinely for asymptomatic people taking isoniazid as preventive treatment in settings able to screen for signs and symptoms of tuberculosis.