Poland's Western and Northern Territories after the Second World War were shaped by overlapping mass population movements, infrastructure destruction, workforce shortages and a high risk of infectious diseases. The aim of this paper is to synthesise public health developments in these territories between 1945 and 1956 and to assess the transition from emergency measures to permanent sanitary and epidemiological surveillance. A narrative historical review of scholarly literature, published statistical sources and legal acts was conducted, including studies on Western Pomerania, Warmia and Masuria, Gdańsk Pomerania, Lower Silesia, Silesia and the Lubusz region. Selected regional data were compared with nationwide figures. In 1945-1947, public health activity was dominated by outbreak detection, isolation, disinfection and delousing, vaccination and restoration of basic services. Typhoid fever, epidemic typhus, dysentery, diphtheria, tuberculosis, venereal diseases and malaria were among the major concerns. The comparisons indicate a clearly elevated burden of some problems, particularly typhoid fever and malaria in selected regions and venereal diseases in the Recovered Territories, while no analogous excess was evident for every infection, as illustrated by diphtheria. In 1948-1951, health services became increasingly centralised and planned, while in 1952-1956 the development of sanitary-epidemiological stations consolidated permanent surveillance. The establishment of the State Sanitary Inspection in 1954 marked the institutional culmination of this transition. Public health was therefore not only a response to epidemiological threats but also part of rebuilding institutions and stabilising everyday life in a region undergoing exceptionally rapid demographic and administrative change.