The aim of this study is to examine women’s night work and conceptions surrounding it, with a special focus on nursing assistants. This is done in part trough a genealocial method and in part discourse analysis of historical as well as contemporary documents. The study is based on a Foucauldian approach in which mainly discourse, power/knowledge, discipline, and problematization are used. The analysis shows that there are a number of different discourses present in both the historical and the contemporary documents, mainly risk discourse and health discourse. The analysis also shows that women in general through these discourses are considered more at risk of certain illnesses and that they appear as vulnerable subjects. At the same time the analysis indicates that night working nursing assistants are marginalized and somewhat unseen in both their work place and in general as far as research is concerned.