The article shows the First World War as a ground-breaking time for the consolidation of the national identity of Lithuanian physicians, and their coordination as a professional group with a precise commitment to the nation and the nation-building process. While physicians’ commitment to hygiene dates from the period prior to the outbreak of the First World War, the war created material conditions which enabled the widespread comprehension of the importance of hygiene in the life of the nation, and the growth of physicians’ sense of professional-intellectual agency within the ethnic community. The need to provide medical aid in a context characterised by epidemics and deteriorating hygiene was a precondition for much stronger coordination among physicians, with the aim of optimising relief efforts. Furthermore, the spread of epidemics was used as a reason for strengthening trust between medical personnel and the population. The difficulties which characterised health care in the early phase of the Lithuanian nation-state (lack of money, shortages, irrational features of the health-care system, etc) made the implementation of the ‘national hygiene’ programme impossible in the short term.