This article argues that the emergence of nosocomial infections as a public health issue is the result of specific socio-cultural processes. An analysis of the French periodical Revue d'Hygiène et de Médecine Sociale over the period 1953-1988 and of the discourse of national actors in the fight against hospital-acquired infections demonstrates that the recognition of nosocomial infections as a public health issue occurred almost independently of objective criteria related to frequency or severity. It is suggested that professional and societal factors provide a better explanation of the emergence of nosocomial infections as a public health issue. Nosocomial infections essentially rescued ?Hygiene', a discipline threatened by the reorganization of the university-hospital system following the 1958 reform. Having entered hospitals, hygienists have had to compete with microbiologists also involved in a subject that has attracted an increasing number of actors from a range of fields. Beyond the development of a public health issue, a battlefield of symbolic fights is thus emerging.