An overview of the forming of the modern Health Administration in Spain is intended, trying to relate proposals with day to day realities. Starting with the dissection of elements that suggested the sanitary backwardness of Spain to contemporary observers, this paper traces the actual program to modernization in public health services through the analysis of the political action led by an élite of doctors and public health administrators, who happened to be at the same time relevant political figures of the dynastic parties, the legal framework of reform (the General Decree of Health, 1904) and the institutional changes in the provisions for public health surveillance; these are labelled "from the Health Boards to the Institutes of Hygiene", symbolizing the moving away from a traditional, pluri-composed and political instance, the Health Board, where experts performed just as advisers, to a new, scientific based and professionally managed institution which, under the Second Republic, extended its benefits to the rural population. The lack of practical effects of these public health reforms led us to conclude that they were suggested more to extend professional areas of competence as well as part of conciliatory policies regarding the "social question".