In the late nineteenth century tuberculosis was endemic in Ireland being responsible for more deaths than any other single cause. There was no medical cure for the disease, although various treatment regimes were tried, some with modest success. In the decade to 1891, 103,314 deaths were attributed to the disease, a ratio of one in every 8.5 deaths. By the late 1960s the contribution of tuberculosis to mortality statistics was insignificant. In 1970, 221 persons died from tuberculosis in the Republic of Ireland, a ratio of one in every 152.4 deaths. In terms of medical disease statistics, this fall in mortality was spectacular. This thesis sets out to explore what was behind this dramatic change. It will do so by examining in detail the key international and national developments pertaining to the treatment of tuberculosis. How did the international understanding of tuberculosis evolve and how did this in turn influence the development of facilities to manage the disease? What models of treatment were followed in Ireland and did they contribute to effecting the change? In what way did the political system retard or accelerate the process of change?