This article, utilizing medical histories and municipal public health reports, focuses on tubercular men, women, and children of the working poor in Buenos Aires between 1885 and 1915. Crowded living conditions and an insanitary working environment increased the poor's susceptibility to tuberculosis. Both public health officials and physicians assumed that the living and working conditions and the immorality of the labouring class encouraged the spread of tuberculosis from their neighbourhoods to those of the elite. The Anti-Tuberculosis League and the efforts of doctors to bring about prevention and cures, which generally mirrored those of the United States and Europe, failed to decrease the death rate from tuberculosis in Buenos Aires between 1885 and 1915. Medical knowledge was limited, while public health officials had neither the time nor funding to change a system that was embedded in the working and living structures of the community. The tubercular poor chose to evade prevention policies and relied on the limited services of sanatoriums, clinics, and hospitals only as a last resort.